SuperSU binaries won't install to my HTC One M8

I am following [this](http://forum.xda-developers.com/showthread.php?t=2708628) guide to root my HTC One M8. I just need root, I don't need a custom ROM. I have gotten to step 7 (weaksauce). I can install weaksauce fine and it roots my device (at least, it says it roots it). However, when I try to run SuperSU (downloaded from the Android market, latest version) it says The SU binary needs to be updated. Continue? It says this in my notification bar as well. I click Continue and it says Installing, please wait. If you see this message for more than five minutes please restart and try again. After about 30 seconds, it says Installation failed ! Please reboot and try again. I've tried it multiple times with all forms of rebooting (adb reboot, holding power button, etc) as well as a factory reset (which put me back down to 4.2.2), however it keeps giving me this error.