error adding computer to workgroup manager

I have a situation where one computer on my LAN cannot be assigned a name because "The name you have chosen conflicts with a name assigned to another computer". My computers are named by location and I would have had a computer previously assigned the name in question, however not any more. If I do a search within Workgroup manager it does not bring up a record for it. I imported this data from an old Tiger server originally so am guessing that is where the problem originated. Does anybody have a fix for this? If it involves using pico please supply the full string as that is not my strong suit.