I know this topic is old but I was having the same weird problem for years. When I was initially trying to find an answer I came across this thread some time ago. Unfortunately, no one had an answer but at least I knew I wasn't the only person in the world who had the problem.
However, it was really frustrating to have to deal with all of that and I decided I needed to know the answer. I remembered this topioc and had it saved in my favorites and decided to go back to it to see if anyone had posted an answer. Unfortunately, no one did, so I continued to try to find a resolution myself.
I finally did! I don't understand actionscript, or why the resolution fixes the problem, I just know it does. When you place the html code in the webpage to embed the Flash movie, there are two areas that say "Allow Script Access Value="", or something like that. The default value Flash gives it is "samedomain". Instead of it saying "samedomain", change it to "always". That will make it work normally. Change both of these sections.
Anyways, I thought I'd just post the answer here to be thoughtful in case somebody out there has the same problem, or if the original poster had not found the answer to the problem yet.