SOLVED - Citrix Xenapp 6.0 hotfix rollup fails to install - Error 1904 Module C:\program files (x86)\citrix\system32\rpm.dll failed to register

When you try to install hotfix rollup on a Citrix Xenapp 6.0, you receive the following error.

To resolve this, leave this window open. And browse to C:\windows\system32\ and rename the file cutildll64.dll to cutildll64.dll.old. Now hit retry and the hotfix should install successfully. after the install completes, reboot the server and then copy the new file from C:\program files (x86)\citrix\system32\cutildll64.dll to C:\windows\system32\.