The suggestion for the OP's problem helped me too:
Running OOTPX as administrator in Vista.
That allowed me to launch the app and enter the Order code. What's strange is I exited the app after it started, and restarted without right-clicking to run ad administrator, and it started back up that time.
So it seems that the first execution on Vista may need to run as administrator.
Anyway, thanks for the support, from here it looks like it might work.
(PS public beta would've found this on day 1
sorry)