Word 2000 templates issue with Word 2007

I have a few word 2000 templates stored in a common location and my VB application calls them from there. This works fine with office 2000 and office 2003, but when i upgraded to office 2007 these templates do not work properly. I always get an error "Sub of Function not defined" and "Microsoft Visual Basic" written in the titlebar of the messagebox. Can anybody help me out solve this issue? Any help is greatly appreciated.