Shared Printers & Folders

Have 30 computers all with WinXP Pro in a Lab that log into an NT4 server. When sharing a printer via LPT1 or mapping a drive to the computer at the front of the room It always gives an error about a shared violation. Upon researching this problem I found out there is a 10 user limit. Is there a registry edit or server function I can do to increase this limit???

Thanks