Reply to Traktor 2 froze??????

I had a gig this past saturday and it was the first time to use the new Traktor 2 pro software with my Traktor S4 and while playing about an hour the software started freezing during my set! The music was still playing but the screen was frozen. Luckily there was another DJ beside that mixed in due to my problems. I've never had this issue on the Traktor S4 software. Any one else have or had this problem????

I have a 2010 MacPro, Mac OS X 10.6.7, 2.53 Intel i5,4 gb 1067 ddr3, 500 gb,

I had all programs closed except traktor and airport off. The memory is only 30 percent full?