Firefox 3

hi,

i have upgraded to firefox 3 and i am noticing problems with some sites i work
on. there isn't a pattern to reproduce the errors, they happen sporadically.
the problem occurs on both my pc and a mac. i am using flash player 9.0 r124.
-one site has quiet a bit of video (flv) and it will freeze sporadically, or
sometimes it will continue playing but without the sound.
-another site will only load part of the flash movie
-another site will not load the video controllers on a swf...the movie always
plays, just sometimes the controllers don't show up.

i have been researching online for similar issues and have tried the following:
-uninstalling and reinstalling flash player
-uninstalling and reinstalling firefox 3
-using firefox in safemode disabling all add ons
-disabling ad blocker (add on from mozilla)
-disable and then enable shockwave plugin
-downloaded flash player 10 beta (this cause other problems with mouse events,
so i uninstalled it)
-installed and earlier version of flash player 9

i'm not sure what this could be. has anyone experienced similar issues?
thanks for any help/advice.