Rooted 5.1.1 not rooted: no superSU

I used Kies to update my previously rooted 5.0.1 Note 4. I now have Android 5.1.1 Lollipop VPU4COG5. With the update, my TWRP recovery was removed. I flashed TWRP recovery 2.8.1.1 via Odin and then, lacking a tar file, downloaded and flashed BeastModeStock 1.0-N910P-OG5.zip, which is shown installed on my phone. Problem is, the phone is NOT rooted. I cannot open superSU, getting a message "There is no SU binary installed, and SuperSU cannot install it. This is a problem!..."

Any suggestions?

Thanks