convert and debug Iphone app from IOS4 to IOS6 in xcode 4.5

Hi, I have simple Iphone app that didn't make it to IOS6 but worked very well with previous version. Xcode gives me some error about "Application windows expecting root controller at the end of application launch". App starts fine but unable to refresh/change tableview after first question of a poll is answered. I know there is some bad code as it was created by non experienced coder so I expect some cleaning/optimizing. The app is Free on Itunes and is named PSScale. I NEED THE JOB DONE QUITE FAST