Personally I've found Firefox to be so flaky on Ubuntu I've stopped
using it in favour of Opera and Chrome. Mozilla seem to have dropped
the ball with Firefox and each new release is getting worse, not
better :-( Only my own opinion / experience but there are so many
alternatives there's little point in trying to fight Firefox any more.

Sad since I've been a huge fan of Firefox for many years.

How did you install FF, from the repositories or from a binary downloaded
from Mozilla?

I reinstalled it from Synaptic.............

Try completely removing using Synaptic (right-click should have this as an
option) or use *apt-get --purge remove firefox*
*
*
The problem is if there is a bad package (and I do not know that is the
case) removing and re-installing does not work because it will not download
a fresh copy but will re-install the bum one from the cache. You need to
remove the application and delete the package and get a fresh one. I am not
saying this will resolve the problem just that re-installing is not always
a solution.

Ill give it a try after I get done with the mail.

I'm getting this symptom as well, under Ubuntu 10.10, Firefox 3.6.23, with one
add-on (Adblock Plus). It seems to be a recent phenomenon, perhaps as a result
of a Firefox update. I haven't done any diagnostic work. I'm just responding
as a "me too", for now.

Yes, there are problems. Mozilla and developers are having problems because
Mozilla is being very aggressive, to keep pace with Google Chrome. Their
frequency of updates causes add-on breakage. We are alll experiencing it.

BTW, maybe you should turn off Add Block plus (just a suggestion). Many
open source groups rely on advertising revenue. Instead use a pop-up
blocker and Flash Blocker. This will cut down band width and at the same
time help out small time developers and start-ups.

Done all of the suggestions and it is working. Thanks for the help. Ill
let you folks know if it happens again.