I found a fix for my problem here
nickpettit.com - blog - HowTo: Fix the Spore Creature Creator 'freezing' problem...
It's addressing crashes in the stand alone creature creator but has fixed the fact that mine crashed when exiting the creature creator. I have had no issues with Spore since following these instructions - b warned through that it does involve installing 3rd party graphics drivers (although from a respected source)
also this fix will only pply to those running Geforce cards
Hope this helps