WorkCentre 6505 won't scan to Computer (Network)

I am not able to use the WorkCentre 6505's "Scan to Network" mechanism to scan to "Network (Computer)". Everytime I select the "Scan to Computer (Network)...", I'm presented with this error:

• Warning
  Cannot Perform This Job Operation

I've tried cycling power (dozens of times), changing network settings, changing scanning defaults, Reseting the scan defaults, adding more computers to the Computer/Server Address Book, and everything else that I can think of short of completely resetting the entire printer.

Does anyone know of any reason that I might be seeing this error (which doesn't appear anywhere in the documentation), or how I can fix the problem?

Thanks for any suggestions.