Hi Anthony;
I had the same issues with my framework moving to PB 12.1 from 11.2. It seems that the Unicode SDK format is key - especially as you move your applications to W7 and again especially its 64 bit O/S.
I also think that a few event timing and firing order changes were introduced in the PB 11.x time frame. So if you don't watch your code carefully in the Activate, Deactivate, Get/LosusFocus, Other, Customer UE's, etc - you can basically "shoot yourself in the foot" when things like this change in the PBVM.
Regards ... Chris