Gapps has stopped. How to fix?
It is recommended to wipe dalvik/cache, factory reset before and after flashing anything in recovery.  

So here are the steps to solve the problem  


Enter CWM recovery mode
Wipe data/factory reset
Wipe Cache partition
Advanced > Wipe Dalvik Cache
Flash Gapps for CM12.1
Wipe data/factory reset, Cache partition
Wipe Dalvik Cache
Reboot