@berty, thanks for the tip on Everything Search, it didn't bring anything up so i'm fairly confident i'm free of it. Still no script error message as of yet since i removed all plugins other than Flash and Acrobat, yours still holding up as well?

Yeah, still no script error. This is the longest I've gone without getting it--about a week now. I also only have Flash and Acrobat plugins running.

For anyone else removing the Quicktime plugin, make sure you delete all the files or the entire folder. There are about six different files just for the one Firefox plugin! They're usually named npqtplugin.dll, npqtplugin2.dll, etc.

Hi everyone, I also had this exact same problem and after reading this thread and following the advice of Danziger (on the first page) the problem went away. Thank you Danziger.

The plugin check page http://www.mozilla.com/en-US/plugincheck/# was very useful. I updated Shockwave Flash and Adobe Acrobat Reader so one of these plugins was causing the problem. I suspect it was Adobe Acrobat reader as this would occasionally produce an error.

bassfoot's solution worked (unchecking cookies) ... but I 'downgraded' to 3.6.17 when my automatic signon feature stopped working and I thought it might have had something to do with all the 'fixes' I tried on this post ... What a difference!

3.6.17 gives a very noticeable performance improvement over 4.0 once you've tried 4.0 for a while (on my weakling Evo n410c laptop running XP)

So my recommended fix for this issue is to upgrade to 3.6.17 from 4.0.

I'm happy to report I still haven't received this error since removing all the Quicktime plugins two weeks ago. I think it's safe to say they were causing the issue.

I went 2-3 weeks without the error having removed all plugins except Flash and Acrobat, but tonight got it again for the first time. However the Microsoft Silverlight plugin had reappeared again (presumably from a Windows Update), have now removed that and fingers crossed the issue will be resolved again.

I have the same problem since upgrading. If I try to let the script continue running, it tries to open Adobe Acrobat and causes the computer to hang (the freezing is related to acrobat as the computer doesn't handle acrobat well).

I have to go into Tools>Options and individually delete the cookies.

Now, I'm having the problem even when I individually erase the cookies.

I found a workaround to this problem but it is not convenient. Before you clear history close Firefox, then re-open Firefox and clear history as you normally would.

Thanks @berty. That's the only one that worked for me on FF 10.o.2

Try disabling "net frame assistant" in Add Ons. I fiddled with several of the fixes suggested in this forum but wasn't 100% successful. Getting rid of the Net Frame is also said to improve overall experience/performance...I tried it & I agree.

Disabling all the old Add-ons that wouldn't update solved the problem.