Well i'm working with him right now.. i just tried that resetting the IE7 & did msconfig from safe mode.. seems like working for the time... But i doubt... it might come again since i don't know the reason for that...
The easiest way of not letting it bother you, is to ignore it by:
Turn off script error reporting in IE7. Tools/Internet Options/Advanced. Then check "Disable script debugging (Internet Explorer)" and "Disable script debugging (Other)," and uncheck "Display a notification about every script error.".