How can I fix NSInvalidUnarchiveOperationException
This is occuring because you are using Xcode 4.5 (or previously the beta) which uses "auto layout" by default. Auto layout is only available on iOS 6 so you will get a runtime error on previous iOS versions.
You can fix this by opening your Storyboard, opening the Utilities pane, and disabling the "Use Autolayout" checkbox in the first tab/section:
For regular non-storyboard nibs, select the top-level view to access this option.