Galaxy S4 rooting problem

Ok guys, all day I have been trying to root my at&t s4 and no luck. The only luck I have been having is getting the root through the cmd prompt and getting superuser. But, when I open superuser and I press insall it says: "There was an error installing Superuser. Please send a log of error to a developer."  There is no logs. Also, I installed TWRP recovery and when I try too boot into it form Clockwork Rom manager it says:

An error occured while attempting to run privileged commands!" 

Somebody help, Thanks!

are you sure the bootloader isn´t locked?

If it is how would i unlock it? How would i find out if its locked or not?

First thing first, Have you ever rooted any other devices before?

Jail breaking an apple device doesn't count....... just saying

I have never rooted any thing before, only jailbroke stuff.

Locked bootloader of the s4? completely locking down bootloaders rarely happens with samsung devices. Normally its not locked at all.

If it is, it's a simple oem unlock with fastloader, just like a nexus device, described in (apperantly there is a nexus-like bootloader lock being used in the states with the "G" version)

(I have more experience with european s4's tho, we never have locked bootloaders on the s4.)