My Sims 3 Doesn't Work!!!!!!!

Hello,

I downloaded Sims 3 onto my ipod touch 2nd gen. a couple of days ago. I think its really good, infact, its probably one of the best games I've played, but since my second renovation its been playing up; freezing, jumping, and turning off. My ipod is only six months old and isn't jailbroken. Does anyone no what to do to make it stop!?
Thanks