Today I updated Adblock Plus addon from v1.2 to v1.3. After restarting Firefox, I realized that Adblock Plus no more blocks ads no matter if I activate or deactivate it. This seems to be a buggy version (e.g. there are some blank lines in its context menu, preferences menu can't be displayed, etc.). The previous version was fine.
How can I roll back a Firefox addon to its previous version?
My Firefox version is 3.6.11 and I'm on Windows XP.