I ran into an issue today where I could not get Hotfix Rollup 3 for Microsoft CRM Outlook Client to install on a Windows 2003 server. The error was:
Action Microsoft.CRM.UpdateWrapper.MspInstallAction failed
This is a 10 server Citrix farm, and I tried a couple of the servers and received the same error. After much research, we found that the original RTM client that was installed probably from the CRM media was a slightly different version than what the rollup was expecting. Oh, and we also tried rollup 2 and 4, but received the same error.
What we finally determined was that we needed a different client installed. So we uninstalled the client, and downloaded this one:
After installing this client, we could apply the Rollup 3 and everything worked as expected. Problem solved!
Tim Rettig's Blog 