I commented out the offending line just to get the build working. Once I did, however, I saw weird behavior with the keyboard when running NGUI Example 0 on my Surface.
If I tap in a text field, the keyboard comes up. When I tap outside the keyboard it goes away. The problem is, this only happens once. Subsequent taps in either of the text fields yield no keyboard... unless I set a breakpoint in the debugger.
If I set a breakpoint on line 604, for example "mKeyboard.active = true;" and run it in the (VS) debugger then the keyboard works correctly every time. Seems like it could be a Unity bug.