Please open c:\windows\wsusofflinupdate.log with a texteditor like notepad and post the content of this file.
What's the username on the affected machines (The name of the user account you are running the computer with?
-> maybe one of our scripts has problems if the username contains special characters.
Are you able to create a new user account with admin rights on these machines ?
Try a new user like "update", give him Admin rights and reboot to this user. Try to install the updates again.