I know this is an old post but I am getting the same thing with classifieds 4.21 integrated with VB
3.8. I get the same IE error on the showproduct page as well as all upload product pages if any text editor is selected. If WYSIWYG and basic are disabled there is no error or if I remove all VB
integration there is also no error. I have tried all variations I can think of with no effect like DHMTL, styles, custom edits, etc. The same issue does not exist in the current release of gallery. I am fine with disabling the editor options but thought I'd mention it ain't quite right compared to gallery.