Steve:
Ended up that you hit it right on the nose.
Now that the panic is over I can focus on evaluating what happened. And, there it is - the MS Hotfix roll-up, uninstalled it and the darn application works again.
Now, if I can just figure out why Citrix HF Rollup 2 causes another app to close before presenting the app to the user, I can install that as well........In testing the application loads, it does everything right, then dies when it tries to initialize its UI.
You didn't install the Microsoft Post SP4 Hotfix Rollup, did you?