xml reader in C#.

Not sure how to do this. Do I build the schema file and use that?
I get an error.  
System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:


Line 44:             ds.ReadXmlSchema(Server.MapPath("GeneralInformation/Countries.xsd"));
Line 45:
Line 46:             DataRow[] drs = ds.Tables["countries"].Select("countryid = '" + ID + "'");
Line 47:             if (drs.Length != 0)
Line 48:             {
 


public string GetCountryName(string ID)
        {
            DataSet ds = new DataSet();
            ds.ReadXmlSchema(Server.MapPath("GeneralInformation/Countries.xsd"));

            DataRow[] drs = ds.Tables["countries"].Select("countryid = '" + ID + "'");
            if (drs.Length != 0)
            {
                return drs[0]["name"].ToString();
            }
            else
            {
                return String.Empty;
            }

        }

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<countries>
  <country countryid="AF" name="Afghanistan" />
 
  <country countryid="AL" name="Albania" />
 
  <country countryid="DZ" name="Algeria" />
 
  <country countryid="AS" name="American Samoa" />
 
  <country countryid="AD" name="Andorra" />
 
  <country countryid="AO" name="Angola" />
 
  <country countryid="AI" name="Anguilla" />
 
  <country countryid="AQ" name="Antarctica" />
 
  <country countryid="AG" name="Antigua And Barbuda" />
 
  <country countryid="AR" name="Argentina" />
 
  <country countryid="AM" name="Armenia" />
 
  <country countryid="AW" name="Aruba" />
 
  <country countryid="AU" name="Australia" />
 
  <country countryid="AT" name="Austria" />
 
  <country countryid="AZ" name="Azerbaijan" />
 
  <country countryid="BS" name="Bahamas" />
 
  <country countryid="BH" name="Bahrain" />
 
  <country countryid="BD" name="Bangladesh" />
 
  <country countryid="BB" name="Barbados" />
 
  <country countryid="BY" name="Belarus" />
 
  <country countryid="BE" name="Belgium" />
 
  <country countryid="BZ" name="Belize" />
 
  <country countryid="BJ" name="Benin" />
 
  <country countryid="BM" name="Bermuda" />
 
  <country countryid="BT" name="Bhutan" />
 
  <country countryid="BO" name="Bolivia" />
 
  <country countryid="BA" name="Bosnia And Herzegowina" />
 
  <country countryid="BW" name="Botswana" />
 
  <country countryid="BV" name="Bouvet Island" />
 
  <country countryid="BR" name="Brazil" />
 
  <country countryid="IO" name="British Indian Ocean Territory" />
 
  <country countryid="BN" name="Brunei Darussalam" />
 
  <country countryid="BG" name="Bulgaria" />
 
  <country countryid="BF" name="Burkina Faso" />
 
  <country countryid="BI" name="Burundi" />
 
  <country countryid="KH" name="Cambodia" />
 
  <country countryid="CM" name="Cameroon" />
 
  <country countryid="CA" name="Canada" />
 
  <country countryid="CV" name="Cape Verde" />
 
  <country countryid="KY" name="Cayman Islands" />
 
  <country countryid="CF" name="Central African Republic" />
 
  <country countryid="TD" name="Chad" />
 
  <country countryid="CL" name="Chile" />
 
  <country countryid="CN" name="China" />
 
  <country countryid="CX" name="Christmas Island" />
 
  <country countryid="CC" name="Cocos (Keeling) Islands" />
 
  <country countryid="CO" name="Colombia" />
 
  <country countryid="KM" name="Comoros" />
 
  <country countryid="CG" name="Congo" />
 
  <country countryid="CK" name="Cook Islands" />
 
  <country countryid="CR" name="Costa Rica" />
 
  <country countryid="CI" name="Cote D'Ivoire" />
 
  <country countryid="HR" name="Croatia (Local Name: Hrvatska)" />
 
  <country countryid="CU" name="Cuba" />
 
  <country countryid="CY" name="Cyprus" />
 
  <country countryid="CZ" name="Czech Republic" />
 
  <country countryid="DK" name="Denmark" />
 
  <country countryid="DJ" name="Djibouti" />
 
  <country countryid="DM" name="Dominica" />
 
  <country countryid="DO" name="Dominican Republic" />
 
  <country countryid="TP" name="East Timor" />
 
  <country countryid="EC" name="Ecuador" />
 
  <country countryid="EG" name="Egypt" />
 
  <country countryid="SV" name="El Salvador" />
 
  <country countryid="GQ" name="Equatorial Guinea" />
 
  <country countryid="ER" name="Eritrea" />
 
  <country countryid="EE" name="Estonia" />
 
  <country countryid="ET" name="Ethiopia" />
 
  <country countryid="FK" name="Falkland Islands (Malvinas)" />
 
  <country countryid="FO" name="Faroe Islands" />
 
  <country countryid="FJ" name="Fiji" />
 
  <country countryid="FI" name="Finland" />
 
  <country countryid="FR" name="France" />
 
  <country countryid="GF" name="French Guiana" />
 
  <country countryid="PF" name="French Polynesia" />
 
  <country countryid="TF" name="French Southern Territories" />
 
  <country countryid="GA" name="Gabon" />
 
  <country countryid="GM" name="Gambia" />
 
  <country countryid="GE" name="Georgia" />
 
  <country countryid="DE" name="Germany" />
 
  <country countryid="GH" name="Ghana" />
 
  <country countryid="GI" name="Gibraltar" />
 
  <country countryid="GR" name="Greece" />
 
  <country countryid="GL" name="Greenland" />
 
  <country countryid="GD" name="Grenada" />
 
  <country countryid="GP" name="Guadeloupe" />
 
  <country countryid="GU" name="Guam" />
 
  <country countryid="GT" name="Guatemala" />
 
  <country countryid="GN" name="Guinea" />
 
  <country countryid="GW" name="Guinea-Bissau" />
 
  <country countryid="GY" name="Guyana" />
 
  <country countryid="HT" name="Haiti" />
 
  <country countryid="HM" name="Heard And Mc Donald Islands" />
 
  <country countryid="VA" name="Holy See (Vatican City State)" />
 
  <country countryid="HN" name="Honduras" />
 
  <country countryid="HK" name="Hong Kong" />
 
  <country countryid="HU" name="Hungary" />
 
  <country countryid="IS" name="Icel And" />
 
  <country countryid="IN" name="India" />
 
  <country countryid="ID" name="Indonesia" />
 
  <country countryid="IR" name="Iran (Islamic Republic Of)" />
 
  <country countryid="IQ" name="Iraq" />
 
  <country countryid="IE" name="Ireland" />
 
  <country countryid="IL" name="Israel" />
 
  <country countryid="IT" name="Italy" />
 
  <country countryid="JM" name="Jamaica" />
 
  <country countryid="JP" name="Japan" />
 
  <country countryid="JO" name="Jordan" />
 
  <country countryid="KZ" name="Kazakhstan" />
 
  <country countryid="KE" name="Kenya" />
 
  <country countryid="KI" name="Kiribati" />
 
  <country countryid="KP" name="Korea, Dem People'S Republic" />
 
  <country countryid="KR" name="Korea, Republic Of" />
 
  <country countryid="KW" name="Kuwait" />
 
  <country countryid="KG" name="Kyrgyzstan" />
 
  <country countryid="LA" name="Lao People'S Dem Republic" />
 
  <country countryid="LV" name="Latvia" />
 
  <country countryid="LB" name="Lebanon" />
 
  <country countryid="LS" name="Lesotho" />
 
  <country countryid="LR" name="Liberia" />
 
  <country countryid="LY" name="Libyan Arab Jamahiriya" />
 
  <country countryid="LI" name="Liechtenstein" />
 
  <country countryid="LT" name="Lithuania" />
 
  <country countryid="LU" name="Luxembourg" />
 
  <country countryid="MO" name="Macau" />
 
  <country countryid="MK" name="Macedonia" />
 
  <country countryid="MG" name="Madagascar" />
 
  <country countryid="MW" name="Malawi" />
 
  <country countryid="MY" name="Malaysia" />
 
  <country countryid="MV" name="Maldives" />
 
  <country countryid="ML" name="Mali" />
 
  <country countryid="MT" name="Malta" />
 
  <country countryid="MH" name="Marshall Islands" />
 
  <country countryid="MQ" name="Martinique" />
 
  <country countryid="MR" name="Mauritania" />
 
  <country countryid="MU" name="Mauritius" />
 
  <country countryid="YT" name="Mayotte" />
 
  <country countryid="MX" name="Mexico" />
 
  <country countryid="FM" name="Micronesia, Federated States" />
 
  <country countryid="MD" name="Moldova, Republic Of" />
 
  <country countryid="MC" name="Monaco" />
 
  <country countryid="MN" name="Mongolia" />
 
  <country countryid="MS" name="Montserrat" />
 
  <country countryid="MA" name="Morocco" />
 
  <country countryid="MZ" name="Mozambique" />
 
  <country countryid="MM" name="Myanmar" />
 
  <country countryid="NA" name="Namibia" />
 
  <country countryid="NR" name="Nauru" />
 
  <country countryid="NP" name="Nepal" />
 
  <country countryid="NL" name="Netherlands" />
 
  <country countryid="AN" name="Netherlands Ant Illes" />
 
  <country countryid="NC" name="New Caledonia" />
 
  <country countryid="NZ" name="New Zealand" />
 
  <country countryid="NI" name="Nicaragua" />
 
  <country countryid="NE" name="Niger" />
 
  <country countryid="NG" name="Nigeria" />
 
  <country countryid="NU" name="Niue" />
 
  <country countryid="NF" name="Norfolk Island" />
 
  <country countryid="MP" name="Northern Mariana Islands" />
 
  <country countryid="NO" name="Norway" />
 
  <country countryid="OM" name="Oman" />
 
  <country countryid="PK" name="Pakistan" />
 
  <country countryid="PW" name="Palau" />
 
  <country countryid="PA" name="Panama" />
 
  <country countryid="PG" name="Papua New Guinea" />
 
  <country countryid="PY" name="Paraguay" />
 
  <country countryid="PE" name="Peru" />
 
  <country countryid="PH" name="Philippines" />
 
  <country countryid="PN" name="Pitcairn" />
 
  <country countryid="PL" name="Poland" />
 
  <country countryid="PT" name="Portugal" />
 
  <country countryid="PR" name="Puerto Rico" />
 
  <country countryid="QA" name="Qatar" />
 
  <country countryid="RE" name="Reunion" />
 
  <country countryid="RO" name="Romania" />
 
  <country countryid="RU" name="Russian Federation" />
 
  <country countryid="RW" name="Rwanda" />
 
  <country countryid="KN" name="Saint K Itts And Nevis" />
 
  <country countryid="LC" name="Saint Lucia" />
 
  <country countryid="VC" name="Saint Vincent, The Grenadines" />
 
  <country countryid="WS" name="Samoa" />
 
  <country countryid="SM" name="San Marino" />
 
  <country countryid="ST" name="Sao Tome And Principe" />
 
  <country countryid="SA" name="Saudi Arabia" />
 
  <country countryid="SN" name="Senegal" />
 
  <country countryid="SC" name="Seychelles" />
 
  <country countryid="SL" name="Sierra Leone" />
 
  <country countryid="SG" name="Singapore" />
 
  <country countryid="SK" name="Slovakia (Slovak Republic)" />
 
  <country countryid="SI" name="Slovenia" />
 
  <country countryid="SB" name="Solomon Islands" />
 
  <country countryid="SO" name="Somalia" />
 
  <country countryid="ZA" name="South Africa" />
 
  <country countryid="GS" name="South Georgia , S Sandwich Is." />
 
  <country countryid="ES" name="Spain" />
 
  <country countryid="LK" name="Sri Lanka" />
 
  <country countryid="SH" name="St. Helena" />
 
  <country countryid="PM" name="St. Pierre And Miquelon" />
 
  <country countryid="SD" name="Sudan" />
 
  <country countryid="SR" name="Suriname" />
 
  <country countryid="SJ" name="Svalbard, Jan Mayen Islands" />
 
  <country countryid="SZ" name="Sw Aziland" />
 
  <country countryid="SE" name="Sweden" />
 
  <country countryid="CH" name="Switzerland" />
 
  <country countryid="SY" name="Syrian Arab Republic" />
 
  <country countryid="TW" name="Taiwan" />
 
  <country countryid="TJ" name="Tajikistan" />
 
  <country countryid="TZ" name="Tanzania, United Republic Of" />
 
  <country countryid="TH" name="Thailand" />
 
  <country countryid="TG" name="Togo" />
 
  <country countryid="TK" name="Tokelau" />
 
  <country countryid="TO" name="Tonga" />
 
  <country countryid="TT" name="Trinidad And Tobago" />
 
  <country countryid="TN" name="Tunisia" />
 
  <country countryid="TR" name="Turkey" />
 
  <country countryid="TM" name="Turkmenistan" />
 
  <country countryid="TC" name="Turks And Caicos Islands" />
 
  <country countryid="TV" name="Tuvalu" />
 
  <country countryid="UG" name="Uganda" />
 
  <country countryid="UA" name="Ukraine" />
 
  <country countryid="AE" name="United Arab Emirates" />
 
  <country countryid="GB" name="United Kingdom" />
 
  <country countryid="US" name="United States" />
 
  <country countryid="UM" name="United States Minor Is." />
 
  <country countryid="UY" name="Uruguay" />
 
  <country countryid="UZ" name="Uzbekistan" />
 
  <country countryid="VU" name="Vanuatu" />
 
  <country countryid="VE" name="Venezuela" />
 
  <country countryid="VN" name="Viet Nam" />
 
  <country countryid="VG" name="Virgin Islands (British)" />
 
  <country countryid="VI" name="Virgin Islands (U.S.)" />
 
  <country countryid="WF" name="Wallis And Futuna Islands" />
 
  <country countryid="EH" name="Western Sahara" />
 
  <country countryid="YE" name="Yemen" />
 
  <country countryid="YU" name="Yugoslavia" />
 
  <country countryid="ZR" name="Zaire" />
 
  <country countryid="ZM" name="Zambia" />
 
  <country countryid="ZW" name="Zimbabwe" />
 
</countries>

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