Many things using the public beta can be opened back in the current shipping version, but if you've enabled an extra feature to test in the public beta, you might not be able to open that project then in the public version.
I think this project might need to stay in the public beta version now.
Now all of my projects that i start from scratch with ordinary premier pro does not open again. It says it was created in a newer version, this really sucks big time. Thinking of moving over to Final Cut, the support told me to download handbrake and load the file in there?! What file? the Premier file? He didnt seem to understand anything..