ODBC datasource wont work on report server!!

Hi,

I have VS2005 and sql server express and ive created some reports using sql server
as a backend. everything works as it should.

THEN...

i created a report that uses a system DSN odbc source and it works in VS2005 it works fine.
i have deployed it to the report server and the datasource appears t be there, but when i try and run the report i ge the following message

An error has occurred during report processing.

An attempt has been made to use a data extension 'ODBC' that is not registered for this report server.anyone got any ideas how i can make this work? i have tried to find an explanation using google, but i cannot seem to see any thing that answers the question.

Regards,

Russ
Express versions of Reporting Services allow for data sources to only be local and must be a matching SKU of SQL Server.