I tossed together a debug version for people experiencing the Invalid Property bug:
Debug1
This is the same as the regular program, but includes a "Debug" option in the Tools menu below Options. That screen has two buttons for testing. They send the calls out to a textbox as they're being made, plus I added error handling (which I don't normally do, obviously) so if/when it throws an error it shouldn't crash the program. If you can't open the Feats/Spells/Enhancements/Destinies/Options screen, post the text from both tests to help me pinpoint the problem.
There's a chance that the Debug screen may throw an error before it even loads. Let me know if it doesn't even load.