samba - Jan 2015 - simple logon script and different results

hi everybody

this is probably something on client (win7 sp1) end, so I hope.
In my very simple logon.bat I have:

xcopy %LOGONSERVER%\netlogon\nsclient.ini 
"%ProgramFiles%\NSClient++\nsclient.ini" /y /q
xcopy /y %LOGONSERVER%\netlogon\nagiosNetinfo.vbs 
"%ProgramFiles%\NSClient++\scripts\nagiosNetinfo.vbs" /q /i

and one client executes it fine whereas the other fails with 
"access denied" and files don't get copied.
On both clients target files already exist and I try to 
overwrite.
What should I check?

thanks
P