The type initializer for ‘System.Data.SqlClient.SqlConnection’ threw an exception.

Test it on a virtual PC running SQL 2000 on a Win 2003 PKLATFORM.
Throws the above error on win 2000 machine with a networked SQL 2000 server
Is this an AD thing???

This could be due to missing references. Or it could be due to an error in the app config file. Is it possible for you to post your code?/

hey it may be the problem with app.config settings.u hv to code like thisif u code this wrongly ,typeintializer error w’ll throw.Also if the key name is used different from app.config also exception will throw.

Yes, check your settings to see if you have one that is a connection string that is conflicting with the one you have.  I had the same problem and that fixed it.