[Alex4]

Everytime I close Firefox i get one or two errors saying:

firefox.exe - Application Error
The instruction at "0x7c90de6e" referenced memory at "0x5f0b001e". The memory could not be "read".
Click OK to terminate the program

Please help me get rid of it.

Add-ons:
AVG Safe Search 8.5 (disabled)
AVG Security Toolbar 2.1.0.7 (disabled)
DownThemAll! 1.1.2
Tab X 2.0