Netware 4.2 SB 5 User Connection-Problem

hi,
i used netware 4.2 sb with 5 user license. we habe 5 pc's an one printserver.
since a few days we have a problem with login on the nw server.

the monitor.nlm show 5 licenses 8 in use !
but we have only 5 pc's

i unplugged the networkcable from the server, so that no user can login.
than i down and start the server. after a few second monitor.nlm show 8
licenses in use, but the networkcable was not insert.

what can i do ?
thanx max