I just experienced this today as well. I found CS5 doesn't seem to like one of my font substitutions. If I use another one, I have no problems.
Works: Helv Neue: Ultra Light Condensed
Crashes: Helv Neue: Medium Condensed
In addition, and this is untested, but I've been finding I need to start Flash first, then open a file (or double-click in my file manager), as well as I need to close the file, and then exit the application. The latter for sure has been causing CS5 to crash when exiting with a file still open (but perhaps it was just the file with the font CS5 didn't care for... again, untested.)
Can you please email your fla to us at FlashAuthBetaBugs@adobe.com? Please note that our filter system cannot accept .zip file. If you are to zip your fla, please change the file extension from .zip to .zzz.
Flash Authoring QE
Hi KDC Amplifi,
What type of text are you using (Classic or TLF)?
I'm using Classic.
All I did was substitute the font with the 'Ultra Light Condensed', then swapped out with 'Medium Condensed' right before publishing. I'd then swap back prior to doing any additional edits, and again before publishing. Rinse and repeat. Although a bit tedious, it worked good (i.e., no issues).
Did you try uninstalling the Medium Condensed and reinstalling it? Also clear your font cache. Sometime that might clear out some bad data and clean up the font.
Well, unfortunately my project is done, at least for now. But I'll bear these in mind should I need to get back into it again. Thanks.
My hope was that perhaps it might help the OP to identify their problem, in that I suffered what appeared to be the same issue.