Hi,
see this KB VMware KB: ESXi/ESX host fails with a purple diagnostic screen mentioning "CpuSchedVcpuSwitch&q...
So you may need to update the BIOS.
cykVM
It could be a result of Intel erratum BT248. Are you running any 32-bit Windows XP guests configured in PAE mode? If so, see the KB article referenced above.
No its Windows 2003 and 2008 Server OS.
thanks
vmk2014
32-bit Windows 2003 can also trigger the issue, unless you have Service Pack 2 installed.