When trying to upgrade a VMware ESX host to 4.0u2 using the VMware vSphere Host Update Utility may fail with the following error message:

 

To resolve this issue you need to change Regional Settings of the computer running the Host Update Utility to English (U.S) or similar:

Close the Host Update Utility and start it again. Should now work fine.

 

http://support.microsoft.com/kb/942460

http://kb.vmware.com/kb/1004767