are you sure you had it setup as a network printer as opposed to a local printer? the Parallel Arbitrator Group is a service that is started in relation to the parallel port which is/was widely used for printers. maybe there is a bug in the driver or something as well. if its not affecting anything, i dont see it being very harmful if you cant find a fix right off the bat. try uninstalling the printer drivers and see if the error goes away and then reinstall to make sure you have everything setup properly. the error will probably come back and if it does, you know exactly whats causing it.
good luck :beer: