Itemframe Spawner crashes game

I tried to create a Itemframe spawner, but my game crashed and everytime I try to start the world up again, my game crashes again.
I have added the crash-report as an attachment.

java.lang.NullPointerException: Saving entity NBT
	at un.b(SourceFile:187)
	at uo.b(SourceFile:168)
	at pk.e(SourceFile:1180)
	at pk.d(SourceFile:1150)
	at add.a(SourceFile:129)
	at add.a(SourceFile:265)
	at bhh.a(SourceFile:19)
	at bhh.a(SourceFile:14)
	at bhh.a(SourceFile:9)
	at bhc.a(SourceFile:114)
	at bhc.a(SourceFile:102)
	at bfr.a(SourceFile:615)