Question [Q] S4 Active AT&T - Help with CWR

I have an S4 Active (SGH-i537 - AT&T), I do not use AT&T as my carrier, and have an ST sim installed.
Currently running 4.4.2
Baseband vs = I537UCUCNE3
Kernal vs = 3.4.0-987011
I have the phone rooted, and SuperSU is installed.
May have an issue with Samsung knox?

Rooted phone via towelroot

I'm trying to get CWR installed so I can install custom ROM's, but all attempts have failed. I have tried to install CWR using steps from xda forums, and also at galaxys4root.

Also tried to use TWRP method, but that fails also.

I have never had a phone this tough to install ROM's on, or to prep for installing them.

Help Please!