reflash the ROM and the gapps but don't flash the theme.
From the Backside thread:
---Updating from a previous BACKside-IHO build
1) Download the newest build, and GreenMachineTheme zip if you like, and place them on your sdcard
2) Boot into recovery and make a backup (imho, not optional )
3) Wipe cache and dalvik cache
4) Flash the BACKside-IHO zip file
5) Flash the GreenMachineTheme (optional)
6) Flash gapps (may not be necessary anymore, ymmv)
7) Reboot and enjoy