Flash Not Working with Firefox

Hi.

I just got a new mbp. (old one's logic board and cpu died)

With my old mbp(leopard) everything flash related was working perfectly fine.
The new mbp, Flash works with every other browsers such as Safari and Opera.

However, when using Firefox to watch videos or browse websites, Flash thinks my left mouse click is my right click. So whenever I try to pause a video or play it, flash opens up "About Flash Player 10"
Its very frustrating.

I reinstalled Flash and Firefox but nothing seems to solve the problem...

Please help me fix this.

Thanks.