render node not rendering

[Morbid Angel]

we got this trouble not long ago. We used to have all boxes rendering on our farm (11 nodes). But recently one render node shows up as idle and it doesnt accept any jobs. It registers on the network and in the manager, but doesnt render...I traced it to this: whenever you have server starting it says 3ds max 6.0 render plugin, then rengisters the server to manager. But on this box the 3ds max 6.0 render plugin is not showing up....any ideas why?