licensing fubar

i have 7-10 machines (depending on how may i have hooked up) on a win2k server network. the machines are win2k, win98se and winxp pro. there are 20 cals purchased as per-server. however, the server stops accepting connections at 6. after that, i get a “no more connections can be made…”
i have played with the licensing MMC till i’ve run out of possibilities. this one has me stumped. any suggestions would be appreciated.
thanks,
freetech