[RESOLVED] Connection String Problem

[Fishcake]

Never entirely sure if these questions belong in Database forum or the language it's written in but....

I've never had this error before and for the life of me can't fix it. The error is

Additional information: Request for the permission of type 
System.Data.SqlClient.SqlClientPermission, System.Data, Version=1.0.5000.0,
Culture=neutral, PublicKeyToken=b77a5c561934e089 failed.

and my connection string is

"Server=mh3-
sqlrpt01;Database=Sales_Campaign;User 
ID=SCUser;Password=******;Trusted_Connection=False"

I've also tried

"Server=mh3-sqlrpt01;Password=******;Persist 
Security Info=False;User ID=SCUser;Database=Sales_Campaign"

but both give the same error.

Any help greatly appreciated as I'm stuck at this point and can't get any further.