Unable to complete setup CyanogenMod 12.1
Problem solved..

The problem persisted only till the time I had been using Open GApps.. Then I checked out for GApps on the official CyanogenMod website and got an idea to try CGApps instead of Open GApps.. So I downloaded the ARM64 package of CGApps and flashed it.. Thankfully it worked for me.. So if someone's facing problems with Open GApps, CGApps is definitely worth a try..