I've got the same problem on:
lars@lones-laptop:/var/log$ lsb_release -a && uname -aNo LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 10.04 LTS
Linux lones-laptop 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 i686 GNU/Linux
I suspect that this makes firefox hang all the time.
I'll attach info in next post. Have to hurry this through before FF hangs.