Root Recovery?

I had my phone rooted using the method on this thread: [ROOT] for LG Optimus G Pro E98x + CWM + TWRP [s-off]
Then installed BlissPop ROM.
Time after that I decided that I can use another superuser app and decided to delete the one I had... and after that I'm not rooted.
Now when I try to do the root from [ROOT] for LG Optimus G Pro E98x + CWM + TWRP [s-off] I get this message from the console:

Press any key to continue . . .
3868 KB/s (1085140 bytes in 0.273s)
cp: can't create '/system/xbin/busybox': File exists
failed to copy 'su' to '/system/xbin/su': Read-only file system
failed to copy 'Superuser.apk' to '/system/app/Superuser.apk': Read-only file sy
stem
chown: /system/xbin/su: Read-only file system


Any ideas how can I fix this?