NT SERVER SYSTEM ERROR IN EVENT VIEWER

yesterday all the domain user couldn’t use the share resource and communicate with other computer in the domain for two hour
i look the system event viewer and find out two stop service in PDC event ID is 2011 & 0
2011-The server’s configuration parameter
“irpstacksize” is too small for the
server to use a local device.Please
increase the value of this parameter.
0-The description for EventID {0} in source
{Srv}could not be found.It contains the
following insertion string{s}:
\Device\LanmanServer

could some one can explain for me why this happaned and how to prevent not to happen again
THANK A LOT!!!!!!!!