Default [Q] [HELP] rooting phone - chainfire not working

Hi guys,

I've tried the search and google multiple times, but the chainfire ( method for rooting phones doesn't seem to work. I've used it successfully with my galaxy s2 in the past, but the s4 doesn't seem to work. Not sure if it's an issue with the Australian version of the device. If someone could point me in the right direction, I would be eternally grateful.

Model - GT-I9505
Android Version - 4.2.2
Baseband version I9505DVUBMG1
Kernel version
se.infra@SEP117 #1
Build number - JDQ39.I9505XXUBMG4
SELinux status - Permissive
Secure boot status - Samsung

Thanks all..