If it's not occurring in Internet Explorer, then you'll have to do some detective work to find the source.

What changed before this problem started?   New software, updates, etc.?   What else do you have running when the errors pop up?

If it is some background program generating the errors, a "clean boot" might isolate it.

http://support.microsoft.com/kb/331796

It could potentially be malware as well.    A full scan with your security software would be a good idea, plus a second opinion from another scanner.  MBAM is a good free one:

http://malwarebytes.org/mbam.php