If you are running a logon script I assume you have Kix in the netlogon directory on the domain controllers. There's really no installing it. Just copy the kix32.exe file there.

My suggestion would be to get back to basics. Create a new installation of windows, join the domain, and then run a very simple test script, not the logon script. If that passes, run the logon script. If that passes, install one program at a time, and re-run logon script.

You should also consider posting your logon script here too.