mobile

I was running factory 5.1 but decided to install cm-12 nightly. Every time I tried it failes no matter what I did. I ried installing cm-11 and that worked but no dice on latest nightly of cm-12. Im rooted unlocked BL and running TWRP 2.8.6.1 when I try to flash the cm12 zip i get this error: error executing updater binary in zip /sdcard download cm-12 2015404 nightly hammerhead zip. Any suggestions.