In the GPO, under scripts you've got your kix-executable and your kix-scriptfile, in the user logon-scripts, you can then set kixexecutable.exe scriptfile.kix . afterwards this is set and replicated out, restart your machine you're testing it on.

First off - make sure like you've done eariler (I think) that your script acctually works. copy it down to a workstation, with a user that's in one or some / all of the groups, run it and verify it. does it work there? Then it should work in your gpo. Mind tho that setting up via a GPO is a bit tricky - using the old way mentioned before -> in each users profile, set the logon.bat and in the netlogon-share place the files (logon.bat, kix-executable and script-file/files).

If you are still go on via a GPO - verify that it acctually gets to the machine and user (gpresult on the machine with the user / wmi-query from the ad-mmc).
Another easy way is to log each logon - make the script write to a file or why not the log. eitherway can be good to use during test-phase.