self.window.rootViewController = self.tabBarController;
Request for member 'rootview controller' in something not a structure or union
what does this error mean?????
You explicitly mention iOS SDK 3.0 in your tags. I'm not sure if that's a mistake since the current SDK is 5.0 and nobody should be developing using iOS SDK 3 any more, but assuming it's not a mistake, the rootViewController property of window wasn't added until iOS SDK 4, so maybe that's why it doesn't work?