Easily replicated, while in-game anytime I press the key for the camping inventory (re-mapped to "N") the client crashed to desktop.

java.util.NoSuchElementException: None.get
at scala.None$.get(Option.scala:322)
at scala.None$.get(Option.scala:320)
at com.rikmuld.camping.EventsC$$anonfun$onKeyInput$1.apply$mcVI$sp(Events.scala:223)
at scala.collection.immutable.Range.foreach$mVc$sp(Range.scala:160)
at com.rikmuld.camping.EventsC.onKeyInput(Events.scala:221)

If you need more of the crash log let me know but this is in version 1.10.2 of minecraft using 2.3d