Win 2K, Fax & WAB

My users have new Dell computers with W2K fax program. The program works faxing from Windows Address Book to an individual and selected individuals but not to groups.

Error Message: "Some recipients were discarded because their addresses don't appear to be fax numbers"

The numbers are valid and work from the individual contact information but not the groups that they are added to. I have tried variations - adding area code etc.