Curious, now I can't start a new game with that custom race, as soon as I select the race it crashes every time.
Please open your debug.err file in notepad, and copy/paste the contents into a post here. This will give us some technical information that can help troubleshoot your problem. The location you'll find the debug.err in varies depending on your game version:
Dread Lords, all versions: C:\Program Files\Stardock\Totalgaming\GalCiv2
Dark Avatar 1.5-1.6 (non-Vista): C:\Program Files\Stardock\Totalgaming\GalCiv2\DarkAvatar
Dark Avatar 1.6+(Windows Vista), 1.7+(non-Vista):My Documents\My Games\GC2DarkAvatar
Twilight of the Arnor:My Documents\My Games\GC2TwilightArnor
Be sure to copy the debug
immediately after the error occurs; if you start the game again, the debug will be erased and recreated for the new session.