supersu binary update failed on 5.0 device.

I've seen one or two threads that were in the same vein as this, but no clear resolution. Every time I open SuperSU, I get the message, "The SU binary needs to be updated. Continue?" I select "Continue," and am given the message to install it normally or through TWRP/CWM. If I try through TWRP, the phone restarts into TWRP, but does nothing. If I select "Normal," I get the "Installation failed!" message. I tried uninstalling/reinstalling SuperSU, but that didn't do anything.
I'm using 5.0 walton device.