What you have is in fact die off on your new rock, which is what has caused the ammonia spike. Make sure you have good water circulation and a good protein skimmer. With uncurred live rock this is not unusual. Frequent water changes should also help keep the ammonia to a minimum during the cureing process (the better you can maintain the water quality the more organisms you will have survive). To light or not to light seems a topic of debate from my experience...I'll leave that part to someone else. The other key factor....Patience. Don't try to add anything else until your rock has fully cured...Patience is a virtue here.