Win 2008 R2 guest shutdown with MONITOR PANIC: vcpu-0:ASSERT error

ESXi: 5.0.0 Build: 4692512

Host server: Dell R710, dual core with 80Gb (10 x 8GB in optimised mode)

Guest: Windows 2008 R2 Web Edition

My Win 2008 guest VM shutdown unexpectedly. The error in the log is: 2012-06-23T17:12:15.352Z| vcpu-2| MONITOR PANIC: vcpu-0:ASSERT vmcore/exts/hv/vt/hv-vt.c:1693 bugNr=676321

Attached is the vmware.log. I've googled the error message and the information I've found indicates this was a known bug in older versions of ESX.

Any and all help would be appreciated.

Thanks,

MR