VMware KB1016070 – ESX 4 Update 01 and HP Management Agents Failed Upgrade
VMware has posted a bug when upgrading ESX 4 to Update 01 with HP Management Agents running. (ESXi is unaffected)
You may have your host end the update unsuccessfully, and in a non-responsive state. To avoid this, disable all the HP Management Agents prior to running the update.
VMware KB1016070 – ESX 4 Update 01 and HP Management Agents Failed Upgrade