How to repair error in Internet explorer?

When I try to open a webmail program while using Internet Explorer I receive the error message "Stack overflow at line 1867. This only occurs on this single program. I have cleaned registry, ran anti-virus and deleted and reinstalled Internet Explorer 8 and deleted and reinstalled the shortcut in my favorites. Truly at a loss. This is localized to this computer so I know it is not the webmail site.