Event ID 6008 - Unexpected shutdown

Hi,

We've received the below error log occasionally on our servers. Mostly and only on windows server 2003 SP2 Std Edition. Googling the event ID mainly points out to heat issue or some sort of memory failure but this server is on a virtualised environment (VmWare esxi 4.1) along with its companion which doesn't have this issue.

However, I did run boot time mem for atleast 3 cycles and no issues were reported.

The hardware is a HP DL 380 G5 and I did run diagnostic tool and all looked good from hardware perspective.

Finally regular AV scans are run and I highly doubt if its a malware attack.

Any suggestions?

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Event Type: Error
Event Source: EventLog
Event Category: None
Event ID: 6008
Date: 18/08/2013
Time: 10:10:15 AM
User: N/A
Computer: XXXXXX
Description:
The previous system shutdown at 8:14:13 AM on 18/08/2013 was unexpected.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 000807dd 00120000 000e0008 022d000d
0010: 000807dd 00110006 000e0016 022d000d