Disappearing Network Printers

I have a NT 4.0 single domain network. All my network printers are installed on my PDC. All my win98 clients have a problem with all network printers disappearing. This seems to happen after a print job from the client has just finished. The printers folder is empty and if a user prints a document they get the “Please install a printer first..” Warning. Only a reboot of the client will restore the printers.