ZCM running on W2K3 SP1.

I've set up a simple App to create a registry key under HKCU\Software.
In Advanced settings I have set it to run as User. When I run the App I
get the following error message on the WS (run either as a normal user
or one with admin privileges on the local WS)

Error generating input file for Registry Action

Looking at the log files under ZCC this error message precedes the
above message

There was an error setting file rights for
4239254962fb3-Registry_Edit-132927Input.xml on Some or all identity
references could not be translated..

The xml file contains the required registry changes. If I run it as
system I don't get any errors but the key isn't created either. Making
changes to HKLM as system works OK. Sticking with ZEN 7 is looking good
at this stage. Hopefully I've just overlooked something