yup! if you flashed an ics rom on a GB phone,then you need new firmware.
in the "you need:" box on the android revolution thread it says:
firmware package from here
are you super CIDed? if so,you can use any of those firmwares. im currently on 3.32.709.108 firmware,but i have used this one: http://goo.gl/RcbMy
from that link