"Internet Explorer has stopped working" error message

I recently started getting an error message when I open Internet Explorer.
after some research i tried disabling different add-ons and found that Avast add-on “avast! WebRep” v7.0.1474.765 is causing the error.
The odd part is that another user on the same system with the same add-on does not cause the error.
Anyone know why or how to correct this?

Windows XP: Click Start> Control Panel> Add or Remove programs> avast> repair

Windows Vista / Windows 7: Click Start> Control Panel> Programs> Programs and Features> avast> repair

Does this happen each time you use IE and each time someone else uses IE?
There might be something else going on.

What OS? Any other security software you have now or ever had and, if uninstalled how was it uninstalled?