machine check error.

[Ttang.uci-750a%rand-relay at sri-unix.UUCP]

I have a question that i like to ask all of you out there. We are running 
4.1absd on our VAX/11-750.  Recently,the system emitted the following
message every one or two hours and unable to recover itself; i.e. it kept on
printing the message until we halted the system and rebooted it.
"machine check 2: cp tbuf par fault
	va 80000ba0 errpc 80018b33 mdr 2f800000 smr 8 rdtimo 0 tbgpar 0
	cacherr 7
	buserr 4 mcesr c pc 80018b33 psl 4150000 mcsr 80314
tbuf par: flushing and returning "

We thought it was a hardware problem and reported to the DEC people.  However,
until now their FEs couldn't figure what's wrong with the system.
I would appreciate if anybody could explain the cause of this error and
how to fix it, or let me know if they had the same problem as we did.
Thanx in advance for all the helps.

/ttang
Csnet:ttang.uci at rand-relay
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