That would normally indicate an error in running something that requires
Visual Basic.  Is the problem only happening when you are reading mails
composed in HTML format?  You might want to read more info about the problem
at this link:

COM: Component Object Model Technologies:
http://www.microsoft.com/com/default.mspx

If the info there does not help, then you should post back adding some added
info about operating system in use, update status of your computer, etc.
Also, the complete, exact text of an error message is always helpful.