Firefox 3.6.8 clicks not working properly for Youtube videos on Ubuntu 10.04 64 bit

[Tapas Mishra]

I am using Firefox 3.6.8 on Ubuntu 10.04
Linux 2.6.32-24-generic #41-Ubuntu SMP Thu Aug 19 01:38:40 UTC 2010
x86_64 GNU/Linux
if I try to pause some video while watching it in Firefox by clicking
on the video area the pause will
not work.Similarly if I try to move the playhead location to some
random position while watching the video
it wont move to the desired place on my system.
To be more sure that this is THE issue before posting here I installed
Chrome 7.0.510
on same 64 bit Ubuntu machine and checked.
The above mentioned problems are not coming on Chrome.
What could be the problem?
Any suggestions?