The Fax Transport does not handle rendering. Rendering is done by the
application in which the file is created. That error message would indicate
that there is no printto verb defined for doc files on that workstation. If
the user has Word 2003, a typical printto verb would be:
"<drive>:\Program Files\Microsoft Office\OFFICE11\WINWORD.EXE" /n /dde

Signature
Russ Valentine
[MVP-Outlook]
> In our SBS 2003 environment, we have Windows XP SP2 workstations that are
> using the fax mail transport in Outlook 2003 SP1.
[quoted text clipped - 10 lines]
> I have tried to uninstall the fax mail transport and reinstall it, but it
> didn't fix the issue.