Oh I didn't realise it was a parallel printer...but then again...you didn't mention it
Anyways, non detection of parallel printers is a known bug introduced in Dapper (6.06) and carry forwarded to Edgy (6.10). It is solved for Fiesty and in latest packages of CUPS for the previous releases of Ubuntu. You need to update your repositories and install the newer packages of CUPS manager.
A workaround would be to modify your /etc/modules file and remove "lp" module from it. Restart your system and the printer should be detected.