As a return to the build 8281?

Help, I set yourself stencyl 3.3 build 8368 now can not run the game in the last version stencyl 8281
Below I have added a log where an error

Reverting to a previous version may not always be possible. I'll add a notice to indicate that the game format changed again.

This particular issue has been fixed for 3.3.1. I.e. if you save your game with 3.3.1, you should also be able to open it again in an earlier version, at least without getting an exception.