To Steve1 -
Some questions that come to mind to help with solving this are:
1) Are you using any ActiveX control components to assist you in accessing the database?
2) Are you using ADO or DAO or ODBC to access your data?
3) When you called the DLL successfully outside of TestStand, what was the OI written in?
4) Since you own the source code, what is the error or exception that is thrown and on what ADO or DAO function call does it fail?
Scott Richardson (NI)
Scott Richardson
https://testeract.com