Unable to uptade the Um jar

Unable to uptade the Um jar

My current ServiceDesk installation is version 9.2 Build 9225.
I am trying to update to Build 9232 (I also treid previous builds though).
Whenever i start the installation, the update manager gave me following error:

"Please restart UpdateManager, unable to update the Um jar".

It then told me to klick the "view log" button for more information, but it is greyed out.
Does anyone experienced the same problem?

                  New to ADSelfService Plus?