RS null cmd in QTI editor

RedScreen on sqs 10.5.7
2016-09-27 10:57:04,216 [ajp-nio2-8020-exec-8] ERROR OLATRuntimeException - OLAT::ERROR ^%^ N20-E3 

 https://xyz.olat.com/auth/RepositoryEntry/97812488/Editor/0
 Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko 
**RedScreen**

<dispatchinfo>
	<componentinfo>
		<compname>vc_exitDialog</compname>
		<compclass>org.olat.core.gui.components.velocity.VelocityContainer</compclass>
		<extendedinfo>page:org/olat/ims/qti/editor/_content/exitDialog.html</extendedinfo>
		<event>	
			<class&gt;org.olat.core.gui.control.Event</class&gt;
			<command>null</command> <tostring>com:null,org.olat.core.gui.control.Event@1f</tostring>
		</event>
	</componentinfo>
	<controllerinfo>
		<controllername>org.olat.ims.qti.editor.QTIEditorMainController</controllername>
		<controllername>org.olat.ims.qti.QTIRuntimeController</controllername>
		<controllername>org.olat.core.commons.fullWebApp.BaseFullWebappController</controllername>
	</controllerinfo>
</dispatchinfo>

>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: null
-> at org.olat.core.gui.exception.ExceptionWindowController.<init>(ExceptionWindowController.java:116)
   at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:57)
   at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:46)
   at org.olat.core.gui.components.Window.dispatchRequest(Window.java:547)
   at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:240)
   at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
   at org.olat.dispatcher.AuthenticatedDispatcher.processValidDispatchURI(AuthenticatedDispatcher.java:275)
   at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:192)
   at org.olat.core.servlets.OpenOLATServlet.executeUserRequest(OpenOLATServlet.java:289)
   at org.olat.core.servlets.OpenOLATServlet.doPost(OpenOLATServlet.java:232)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
>>> stack of 2.cause::java.lang.NullPointerException: null
-> at org.olat.ims.qti.editor.QTIEditorMainController.event(QTIEditorMainController.java:487)
   at org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:202)
   at org.olat.core.gui.components.AbstractComponent$1.run(AbstractComponent.java:240)
   at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
   at org.olat.core.gui.components.AbstractComponent.fireEvent(AbstractComponent.java:238)
   at org.olat.core.gui.components.velocity.VelocityContainer.doDispatchRequest(VelocityContainer.java:113)
   at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
   at org.olat.core.gui.components.Window.doDispatchToComponent(Window.java:1143)
   at org.olat.core.gui.components.Window.dispatchRequest(Window.java:356)
   at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:240)
   at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)