1. Can you compile the project without error on the "offending" machine?
2. Check for a missing reference.
3. If you're using the ADODB Library, remove the reference to it (Microsoft ActiveX Data Objects 2.x Library - x may vary: 2.0, 2.1, 2.5, 2.7, 2.8) and recompile (this will yield an error), then add the reference back and recompile. I sometimes get this kind of error when porting an Access project using ADO from a pc to another and that solution works for me.