Beut,
Your msg states that the device needs to be rooted before it can be downgraded from 5.0.2.
I'm running 5.1.1 on a NotePro SM-P905V (Verizon LTE) and I'm unable to root it using Odin and TWRP viennaltexx 2.87 apparently b/c it has a locked bootloader. I was thinking that my only option...