Your script
ECHO ON
IF "%OS%" == "Windows_NT" goto NT_OS
z:\kix32.exe z:\PLogon9x.kix
EXIT

:NT_OS
kix32.exe PLogonNT.kix
EXIT
Has error because, not spectify path

I keep kix32.exe in \\bstl_svr1\netlogon, I must specify path for kix32

My Script
ECHO ON
IF "%OS%" == "Windows_NT" goto NT_OS
\\bstl_svr1\netlogon\kix32.exe \\bstl_svr1\netlogon\PLogon9x.kix
EXIT

:NT_OS
\\bstl_svr1\netlogon\kix32.exe \\bstl_svr1\netlogon\PLogonNT.kix
EXIT
**

I put PLogon.bat in Profile (User property)
Also It has no error with PLogon.bat.
An Error has occurred with PLogonNT.kix

Pech