A quick note about getting lots of errors when building your cocos2d app under Xcode 5.1 and iOS 7.1. It took me by surprise after updating Xcode, so I thought I post this.
Cocos2D 2.x is not 64-bit ready. So you will need to set your Architecture to 32-bit.
Select your target.
Choose Build Settings.
Change the Architecture to $(ARCH_STANDARD_32_BIT).