What recovery are you using, hopefully clockworkmod ;-) You will have to wipe in the partitions menu. Boot, data, cache and system. Do not wipe sd, obviously! Then flash rom and gapps. Reboot
Thanks Andy. After Formating all the above partitions and flashing both the rom and gapps before rebooting I am up and running GB with out any unknown issues.
Thanks again for the help.

