I'm having some problems with an app on the computers of some of the people testing it. They're getting this error upon start up of the app

System.Runtime.InteropServices.COMException (0x80040154): Retrieving the COM class factory for component with CLSID {00000100-0000-0010-8000-00AA006D2EA4} failed due to the following error: 80040154.

There are only three COM references in my project - one of them is dao.dll - the app works fine for some people but for the two it does not at least one of them is using Vista 64 bit (the other I am still waiting to hear on his o/s but I'm guessing its 64 bit). Does DAO cause problems with 64 bit systems and if so should I just remove all the DAO and make it ADO.NET code or is there some other kind of workaround?

The app is being installed on the 64 bit machine to C:/Program Files(x86) - is there a different install path that would help the app run? Is it possible this issue has nothing to do with a DAO and Vista 64 bit link?

The error does not point directly at a line of code - only the module that contains it and in the declarations of that module is

Friend DAODBEngine_definst As New dao.DBEngine

which is why I am assuming this is dao related.

Any help would be appreciated.