File sharing limit in Win2K Pro?

I recently deployed a Workstation with Win2000 Professional to use as a light-duty file server for a user group of about 20. After I set up the share and underlying file structure, users were able to log in and use the files until there were 10 connections, after which all subsequent users were denied access. Is this a setting that can be modified somewhere? I searched the registry and could not locate a likely candidate. Any other known workarounds other than install NT 4.0?

Thank you.