I'm also having this problem and I'm working on a very important project right now. If you find a solution please post it here. Here's a link to another person suffering from the same issue.
I had an existing Flash website, opened CS4 received Arial font no good. Looked up the solution. At Microsoft is said that the mappings were confused by the names used for arial, no problems download the patch.
Next time still the error message PLUS now the fonts come up as a combination of symbols best described as rubbish. I wanted arial, plain old no nonsense arial.
Any tips to overcome the patch?
Also had a crash like this one
He feels it is not a font problem but a stability issue.
Uninstal arial MT that's the only solution I found
Did you try the Microsoft arial hotfix solution? It downloads office-kb956514-fullfile-x86-glb
I looked for arial MT - not listed under the fonts
I uninstalled Arial MT and that seemed to work. I really wish we could find a better solution. That will have to work for now, but uninstalling the font is a pretty crappy fix. What I can't figure out is...is this a problem with Microsoft or Adobe or both. It seems to me that it is probably a bug with Adobe Flash.
The thing is we have 3 machines running Flash CS4 and all three have this same issue, so this has to be a pretty universal problem. You would think Adobe would have addressed this by now.