How do I debug an XML schema?

How do I figure out what is erroring?  SOmeone suggested I opent his file in a brwoser window - when I did - the first line returns in all red - does this mean it is an error?  Hate to be stupid - but our web guy is not helping with this - we are trying to get an application to use integrated security.  The only error the app provides is File not loaded.
We are working on AIX- the software is Hyperion Essbase.  
--------------------------Actual File With confidential info removed---------------------------------
<?xml version="1.0" encoding="UTF-8" ?>
- <css xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> THIS IS LINE THAT RETURNS IN RED
- <spi>
- <provider>
- <msad name="msad1">
  <trusted>false</trusted>
  <url>ldap://companyusa.corp.company.com:636/dc=companyusa,dc=corp,dc=company,dc=com</url>
  <userDN>CN=XAPSAAB,OU=Users,OU=IS,DC=companyusa,DC=corp,DC=company,DC=com</userDN>
  <password>userPassword</password>
  <authType>simple</authType>
  <authProtocol>ssl</authProtocol>
  <identityAttribute>dn</identityAttribute>
- <user>
  <loginAttribute>sAMAccountName</loginAttribute>
  <fnAttribute>givenname</fnAttribute>
  <snAttribute>sn</snAttribute>
  <emailAttribute>mail</emailAttribute>
- <objectclass>
  <entry>person</entry>
  <entry>organizationalPerson</entry>
  <entry>user</entry>
  </objectclass>
  </user>
- <group>
  <nameAttribute>cn</nameAttribute>
- <objectclass>
  <entry>group?member</entry>
  </objectclass>
  </group>
  </msad>
  </provider>
  </spi>
- <searchOrder>
  <el>msad1</el>
  </searchOrder>
- <token>
  <timeout>60</timeout>
  </token>
- <logger>
  <priority>DEBUG</priority>
  </logger>
  <securityAgent name="NETEGRITY" />
  </css>Start Free Trial