"Faild to ack TLB invalidate" でぐぐったら VMware ESX Server 3.0.3 Release Notes が見つかって、
ESX Server Stops Responding and Displays a Purple Screen
This release fixes an issue where ESX Server stops responding, and displays a purple screen with the error message Failed to ack TLB invalidate.
http://www.vmware.com/support/vi3/doc/releasenotes_esx303.html
ESX 3.0.3 では直ってるらしいが EXSi はまだなのか?