Win2K Event ID 2019

Has anyone had to deal with this error
before? The text of the description is
as follows: The server was unable to
allocate from the nonpaged pool because
the pool was empty.

This error was repeatedly displayed in
the event viewer every time anyone tried
to access the server until I rebooted
it. No one could see the network, but
the server could see the network and
interact with it. One user had tried to
dial in to the server the evening
before, and couldn’t log in. Everyonewas able to see the network after I
rebooted the server.

What causes this error, and what caused
the server to prevent the workstations
from seeing or logging on to the
network? My knowledge of NT 4.0 doesn’t
go this far.