We're getting the same message on our 7900. Numerous attempts to clean have all failed, as has rebooting the machine. Nozzle check reveals that only the Light Light Black is affected; even trying a nozzle clean on an unaffected pair failed, though. Everything else is perfect on the nozzle check. I guess all heads are involved regardless of which pair you're cleaning? Meantime, I've disabled the auto clean function, as I read that too many failed cleanings will generate an unrecoverable error (RET100), and you can't use the machine. That nozzle clean plot, showing the light light black as missing in the middle, is a possible sign the printhead itself is on the way out.
Has anyone tried the Epson cleaning cartridges?