870 and 800 MB cdrs?
I didn't think that was possible. Besides that, most cd-recorders are capable of recording that type of CD. Check back with the guy at work and make sure it is a standard cd-burner he is using. If you are not careful, you can really screw up your burner.
EDIT: read this too, it might help a bit -
http://club.cdfreaks.com/showthread....ht=overburning