I was trying to install ESXi 4.0 Update 1 onto existing ESXi 4.0 system. It did not work. Either VMware CLI or Host Update Utility did not work. Particularly Host Update Utility was saying “An error has occured. Download failed“. I tried to download the .zip file with the update and install it. Host Update Utility checked that it is correct and failed again. I spent the entire morning looking for the solution without any success.
And, thank you, Roberto Rosa (http://communities.vmware.com/thread/220489), you gave me the idea how to resolve the issue. No, I should say THANK YOU, ROBERTO!
This is an XML parsing problem in VMware product. My Windows is EN-US edition with additional language installed. Just the second language! But HUU does not work. I installed Host Update Utility on another computer with pure EN-US Windows. Everything works. Just works.