I have an Excel project that connects to an SQL database via ADO. It works fine in Windows XP and also works on certain Windows 7 machines but crashes on a couple of newer Windows 7 machines. All machines are running Excel 2010. All of the XP machines are 32 bit, all of the Windows 7 machines are 64 bit.

Stepping through the code, it crashes when a procedure involving database access is called for the first time, but does so immediately upon calling the procedure. If I put a breakpoint at the beginning of that procedure, it is never reached. The error message received when debugging is "The object invoked has disconnected from its client".

I'm sure that this has to do with the changes to ADO that were implemented with Windows 7 SP1 and I'm sure that I probably installed something on the working Windows 7 machines six months ago when I first implemented database functionality, but I can't figure out what that was, nor have I been able to find anything useful via Google. msado60_Backcompat_x64.tlb is properly referenced on all of the 64 bit machines, so that's not the issue.

Any suggestions?