Netware 6.5 SP7

One of our servers abends on an almost daily basis.
The server does not go off it is just frozen, I have to use the power button to re-start it.
Normally there isn't anything in the abend log but yesterday there was.

The relevant part of the abend log is attached.

A summary is shown below:
Server RJD02 halted Sunday, 16 August 2009 4:29:39.029 am
Abend 1 on P00: Server-5.70.07: Nonmaskable Interrupt Processor Exception (Error code 000000B0)
Additional Information:
There may be some bad memory either on an adapter card or on the motherboard. If the problem continues, try replacing the main system memory or adapter cards to prevent future parity errors.