I've tried that too, no joy
Apparently I can download the firmware and re-flash that.
http://www.sammobile.com/firmware/?page=3
Worth a try I guess.
You could try that shouldn't do it any harm.
You could also try the noob proof method of flashing CM9
In this thread http://forum.xda-developers.com/showthread.php?t=1419102 Under: CM9 Resurrection Edition for use with Odin. Make sure Odin is running in admin mode also.