So, I spent WAYYYYY too much time on this over the weekend, but finally found some answers. Finally! First, the core problem appears to be permissions based. I accidently stumbled upon this once I found the wimgapi function WIMRegisterLogFile. The information contained in the log files led me to UAC permissions. However, I don't understand why the Mount calls returned successful when in fact they were failing. Strange. Secondly, there is still something funky with using the proper DLLs. "If it ain't broke don't fix it", right? Well, it's working for me right now so I will continue debugging the app, then come back to troubleshooting the dll problems once I start building the install routines. Anyway, thanks for leading me down the right path. The world suddenly makes sense again, and my sanity is still intact! Life is good!