Flash 10 breaks Flash 8 Content

Question

I have a Flash 8 set of movies originally developed in CS3, we recently updated most all computers to Flash 10. Without touching the content it stopped working correctly in one perculiar spot. Going to a computer with Flash 8 installed it works fine.
In this case I have a base movie that loads 22 different SWFs depending on button clicks on the base movie. The loadable SWFs simply have a Play() and Stop() AS2 code in them, no other ActionScript, although there is audio, text and animation in the movies. One of the 22 slides loads and plays about 5 seconds of the timeline, then halts everytime. All other movies in the set play properly end to end. Size is not an issue either since this one is middle of the road for the entire 22 at only 528K.
As I said the content has not been touched since originally produced, the only variable I can identify is the upgrade to Flash 10. I did think maybe something in the company deployment of 10 might cause it, but my 3 personal computers do the very same thing and I have even setup a clean Virtual PC with the same results.
Any ideas of what might be casuing this issue?

Answer 1

There have been some recent changes to the security policies implemented in Flash Player 10. Maybe you can review since you are loading external SWF files:
http://www.adobe.com/devnet/flashplayer/articles/fplayer10_security_changes_02.html
Aside from security, not sure but you might try breaking down the presentation to just the problem SWF loading and see how it behaves.
Also you might want to make sure your audio on that slide is set to streaming or maybe the audio only plays once and the file stops because of no instructions.
In addition sometimes the Flash Player does not install properly into the browser. I had this experience and Adobe now has a flash player uninstaller that worked good for me. Make sure you reboot after reinstalling.
http://kb2.adobe.com/cps/141/tn_14157.html