I have that problem as well. I've barely started the game and mine says something like 1000.7% completion. What's up with that?
When I played for a half hour, I got 19% complete. That really means 1.9% complete.
My friend thinks that 1000% completion is finishing the game. he has only to [beat the final boss] to finish the game.
Update: my friend finished COR on the ADARA 512mb. He has 1000% completion. He saw his first lock up at one of the teleport locations. He has now had 2 lockups at diff teleport locations. They are random and do not occur everytime. This only started after he beat the final boss...