It sounds like a permissions problem. Get it to work this way:

1. Share the proper location. -- \\server\share\filetorun.exe

2. Set permissions on the share folder (doublecheck to see if you can execute file outside logon script from remote PC under proper userid as well) to allow executable access for whoever is running the logon script (domain\everyone?)

3. execute from the logon script with:

SHELL "\\server\share\filetorun.exe" or
SHELL "%comspec% /c \\server\share\filetorun.exe > nul"

Brian