Try this go to administrative tools on the Orion Server hosting Orion and select Data Sources (ODBC). Once the window is up, click on the Drivers tab.
Let me know if you have drivers for SQL Server.
Look at the attached screen shot.
Yes I have that on my Orion server>
Sometimes when you have performed an upgrade from SQL 2000 to SQL 2005 the account you are using may not correctly follow onto the new install of SQL.
Creating a new user to connect to the Database may correct this issue.
If you are using the defaulf SolarWindNPM then make new user SolarWindsNPM1.
We (managed to get a DBA to help) have already tried this and get the same error.