I am getting the following error while trying to authenticate agains active directory, any ideas?? asp.net 2.0 vb.net

asp.net 2.0 vb.net
I am getting the following error while trying to authenticate agains active directory, any ideas??
Below is my config file


Configuration Error
Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.
Parser Error Message: Object reference not set to an instance of an object.
Source Error:
Line 60:                         <add
Line 61:                            name="MyADMembershipProvider"
Line 62:                            type="System.Web.Security.ActiveDirectoryMembershipProvider,
Line 63:                            System.Web, Version=2.0.0.0, Culture=neutral,
Line 64:                                              PublicKeyToken=b03f5f7f11d50a3a"
Source File: C:\SourceCode\ADAuthTest\ADAuthTest\web.config    Line: 62


----------------------------------------------------------------------------------------------------------------------------------------------------------------
<?xml version="1.0"?>

<configuration>
    <appSettings/>
      <connectionStrings>
            <add name="ADConnectionString" connectionString="LDAP://extremefitness.local/CN=Users,DC=extremefitness,DC=local" />
      </connectionStrings>
      
    <system.web>
        <compilation debug="true" strict="false" explicit="true" />
            <authentication mode="Forms">
                  <forms name=".ASPXAUTH" loginUrl="frmLogin.aspx"
                           defaultUrl="default.aspx" protection="All"
                           timeout="20" path="/" requireSSL="false"
                           slidingExpiration="true" cookieless="UseDeviceProfile"
                           enableCrossAppRedirects="false">
                        <credentials passwordFormat="SHA1"/>
                  </forms>
            </authentication>

            <authorization>
                  <deny users="?" />
                  <allow users="*" />
            </authorization>

            <membership defaultProvider="MyADMembershipProvider">
                  <providers>
                        <add
                           name="MyADMembershipProvider"
                           type="System.Web.Security.ActiveDirectoryMembershipProvider,
                           System.Web, Version=2.0.0.0, Culture=neutral,
                                             PublicKeyToken=b03f5f7f11d50a3a"
                           connectionStringName="ADConnectionString"
                           connectionUsername="extremefitness.local\administrator"
                           connectionPassword="xxxxxxx"
                           attributeMapUsername="sAMAccountName"
                     />
                  </providers>
            </membership>
    </system.web>
</configuration>