BSOD with 4.1150349.920, Thunderbird, and Outlook on WinXP SP3

I recently updated Thunderbird to 3.1.1 and started to get BSOD when running the program, especially when Outlook 2007 is also running. They run ok for a few minutes, then BSOD with a corrupt minidump that seems to point to thunderbird.

If I run Comodo with AV/firewall/D+ set to disabled, the two programs seem to run fine together.

Any ideas?