Erreur librairie Keypad

java.lang.NullPointerException
	at processing.app.debug.Compiler.compile(Compiler.java:75)
	at processing.app.Sketch.build(Sketch.java:1412)
	at processing.app.Sketch.compile(Sketch.java:1203)
	at processing.app.Editor$44.run(Editor.java:1807)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Voila mon erreur sous arduino 0018