Execute when user log on

I need that every time that an user log on a Client PC (Windows 2000 Workstation) on a Windows 2000 domain executes a task:
C:\WINNT\system32\xcopy.exe “C:\Arxius de programa\Inici\Microsoft” “C:\Documents and Settings\%username%\Dades de programa\Microsoft” /s /y . This will copy 3 files (on 2 folders) to all users that log on this PC.
I set up a policy that on “User configuration/Admin templates/System/Log on-Log off” has this command line but when the user log on nothing happens!
What I’m making wrong? It’s possible to make that? I need to copy this 3 files to all the users (500). Is there another path to achieve that?
Thanks a lot