Machine startup GPO

Hello.

I have a GPO that executes a script at machine startup (VBScript) that are
checking some reg values if one of our applications should be fresh
installed, upgraded or is up to date. It also copies some files when run the
first time and some other small stuff.

It have been working fine here for say 3 years on both XP and w2000 machines.
Now i am trying to implement Vista machines here. But they refuse to execute
the script or as it seems, even start reading it.

I have tested with just a simple vbscript, but that dont run either.
In the GPO at logon is "Allwyas wait for the network......." enabled
There are no WMI filters enabled.

I have copied the script to the Vista computer and manually run it there
without any probs.

The Vista machines are up to date with the all available MS-patches and sp.
I have also tested to apply a simple logon script, a bat-file that sets the
time to match one of our servers to the domainadmin account and logging on
the Vista machine as admin but the logon script dont run either. The UAC is
deactivated.

Any clue how i can fix this?
--
/Jimmy