Windows 2003 shared Fax blocking all

[Uwe]

Faxing on my Windows 2003 server has been working fine for a couple of years.
All of a sudden I try to fax from my workstation and I get the message that
the fax is blocked and the wizard quits.
This happened out of the blue.
When I start the FAX SERVICE MANAGER iget an error "Failed to load coverpage
node"
When I do the properties in the service manager I cannot uncheck the 3
disable checkboxes on the general tab. I get "Unexpected Error" when I
uncheck them and click APPLY.
HELP
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Thanks,
Uwe