The real problem may be that Adobe Flash is notoriously buggy, and they basically handed off linux development to Google. You can install Google Chrome for linux, which has better support than Firefox, or just follow this link:
http://www.youtube.com/html5
HTML5 is in the process of replacing Adobe Flash on the web anyway, and about time too.
Not sure what to do about fixing Flash Player (although I may see something once I put effort into it), but this is a potential good workaround.