833987 didn't install on one server

On W2003 server I get the following errors either when installing 833987
using SUS (v4) or manually:
- Windows Update Log:
Install Set Restore Point (Error 0x00000078: This function is not supported
on this system)
-> Rubbish, we're on a server
and
See iuhist.xml for details: Install finished (Error 0x8007000D: The data is
invalid.)
-> iuhist.xml doesn't show anything useful.

In the eventlog I have "Source: Automatic Updates, Event ID: 20,
Installation Failure: ... KB833987)

FYI: TimeZone settings are OK, there's nothing like a "system restore point"
on a server and I tried a) downloading from the windowsupdate site and b)
executing the patch manually (-> "The data is invalid")

Anybody?