Error when deleting an app

[2015-12-15 20:37:58,701]  INFO - assets_router:jag Emitting event : login
[2015-12-15 20:38:14,362]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:14,362+0530]
[2015-12-15 20:38:15,397]  INFO - SSOConfiguratorUtil SSO Provider : wso2is 5.0.0 for eee-tenant1.com-1.0.0 is Successfully Deleted
[2015-12-15 20:38:16,195]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:16,195+0530]
[2015-12-15 20:38:16,281]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:16,281+0530]
[2015-12-15 20:38:18,605]  INFO - assets_router:jag Emitting event : login
[2015-12-15 20:38:20,874]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:20,874+0530]
[2015-12-15 20:38:21,446]  INFO - SSOConfiguratorUtil SSO Provider : wso2is 5.0.0 for ggg-tenant1.com-1.0.0 is Successfully Deleted
[2015-12-15 20:38:22,025]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:22,025+0530]
[2015-12-15 20:38:22,097]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:22,097+0530]
[2015-12-15 20:38:23,468]  INFO - assets_router:jag Emitting event : login
[2015-12-15 20:38:27,705]  INFO - assets_router:jag Emitting event : login
[2015-12-15 20:38:28,080]  INFO - assets_router:jag Emitting event : login
[2015-12-15 20:38:31,710]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:31,710+0530]
[2015-12-15 20:38:32,227]  INFO - SSOConfiguratorUtil SSO Provider : wso2is 5.0.0 for cccc-tenant1.com-1.0.0 is Successfully Deleted
[2015-12-15 20:38:32,799] ERROR - WebAppManager org.mozilla.javascript.EcmaError: TypeError: Cannot read property "id" from null (artifacts#31)
org.jaggeryjs.scriptengine.exceptions.ScriptException: org.mozilla.javascript.EcmaError: TypeError: Cannot read property "id" from null (artifacts#31)
	at org.jaggeryjs.scriptengine.engine.RhinoEngine.execScript(RhinoEngine.java:571)
	at org.jaggeryjs.scriptengine.engine.RhinoEngine.exec(RhinoEngine.java:273)
	at org.jaggeryjs.jaggery.core.manager.WebAppManager.execute(WebAppManager.java:536)
	at org.jaggeryjs.jaggery.core.JaggeryServlet.doGet(JaggeryServlet.java:24)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:735)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:378)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
	at org.jaggeryjs.jaggery.core.JaggeryFilter.doFilter(JaggeryFilter.java:21)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.wso2.carbon.tomcat.ext.valves.CompositeValve.continueInvocation(CompositeValve.java:178)
	at org.wso2.carbon.tomcat.ext.valves.CarbonTomcatValve$1.invoke(CarbonTomcatValve.java:47)
	at org.wso2.carbon.webapp.mgt.TenantLazyLoaderValve.invoke(TenantLazyLoaderValve.java:56)
	at org.wso2.carbon.tomcat.ext.valves.TomcatValveContainer.invokeValves(TomcatValveContainer.java:47)
	at org.wso2.carbon.tomcat.ext.valves.CompositeValve.invoke(CompositeValve.java:141)
	at org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:156)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
	at org.wso2.carbon.tomcat.ext.valves.CarbonContextCreatorValve.invoke(CarbonContextCreatorValve.java:52)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1736)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1695)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:744)
Caused by: org.mozilla.javascript.EcmaError: TypeError: Cannot read property "id" from null (artifacts#31)
	at org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3687)
	at org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:3665)
	at org.mozilla.javascript.ScriptRuntime.typeError(ScriptRuntime.java:3693)
	at org.mozilla.javascript.ScriptRuntime.typeError2(ScriptRuntime.java:3712)
	at org.mozilla.javascript.ScriptRuntime.undefReadError(ScriptRuntime.java:3725)
	at org.mozilla.javascript.ScriptRuntime.getObjectProp(ScriptRuntime.java:1483)
	at org.mozilla.javascript.gen.artifacts_23._c_anonymous_2(artifacts:31)
	at org.mozilla.javascript.gen.artifacts_23.call(artifacts)
	at org.mozilla.javascript.optimizer.OptRuntime.callName(OptRuntime.java:63)
	at org.mozilla.javascript.gen.artifacts_23._c_anonymous_12(artifacts:187)
	at org.mozilla.javascript.gen.artifacts_23.call(artifacts)
	at org.mozilla.javascript.optimizer.OptRuntime.call1(OptRuntime.java:32)
	at org.jaggeryjs.rhino.publisher.modules.security.c1._c_anonymous_6(/publisher/modules/security/storage.security.provider.js:82)
	at org.jaggeryjs.rhino.publisher.modules.security.c1.call(/publisher/modules/security/storage.security.provider.js)
	at org.mozilla.javascript.optimizer.OptRuntime.callN(OptRuntime.java:52)
	at org.jaggeryjs.rhino.publisher.controllers.c3._c_handleResourceRequest_2(/publisher/controllers/storage_router.jag:64)
	at org.jaggeryjs.rhino.publisher.controllers.c3.call(/publisher/controllers/storage_router.jag)
	at org.mozilla.javascript.optimizer.OptRuntime.callName(OptRuntime.java:63)
	at org.jaggeryjs.rhino.publisher.controllers.c3._c_anonymous_1(/publisher/controllers/storage_router.jag:45)
	at org.jaggeryjs.rhino.publisher.controllers.c3.call(/publisher/controllers/storage_router.jag)
	at org.mozilla.javascript.ScriptRuntime.applyOrCall(ScriptRuntime.java:2430)
	at org.mozilla.javascript.BaseFunction.execIdCall(BaseFunction.java:269)
	at org.mozilla.javascript.IdFunctionObject.call(IdFunctionObject.java:97)
	at org.mozilla.javascript.optimizer.OptRuntime.call2(OptRuntime.java:42)
	at org.jaggeryjs.rhino.publisher.modules.c6._c_anonymous_17(/publisher/modules/publisher.js:438)
	at org.jaggeryjs.rhino.publisher.modules.c6.call(/publisher/modules/publisher.js)
	at org.mozilla.javascript.optimizer.OptRuntime.call0(OptRuntime.java:23)
	at org.mozilla.javascript.gen._store__server_js_11._c_anonymous_17([store]/server.js:284)
	at org.mozilla.javascript.gen._store__server_js_11.call([store]/server.js)
	at org.mozilla.javascript.optimizer.OptRuntime.call2(OptRuntime.java:42)
	at org.jaggeryjs.rhino.publisher.modules.c6._c_anonymous_16(/publisher/modules/publisher.js:433)
	at org.jaggeryjs.rhino.publisher.modules.c6.call(/publisher/modules/publisher.js)
	at org.mozilla.javascript.optimizer.OptRuntime.callN(OptRuntime.java:52)
	at org.jaggeryjs.rhino.publisher.controllers.c3._c_script_0(/publisher/controllers/storage_router.jag:8)
	at org.jaggeryjs.rhino.publisher.controllers.c3.call(/publisher/controllers/storage_router.jag)
	at org.mozilla.javascript.ContextFactory.doTopCall(ContextFactory.java:394)
	at org.mozilla.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3091)
	at org.jaggeryjs.rhino.publisher.controllers.c3.call(/publisher/controllers/storage_router.jag)
	at org.jaggeryjs.rhino.publisher.controllers.c3.exec(/publisher/controllers/storage_router.jag)
	at org.jaggeryjs.scriptengine.engine.RhinoEngine.execScript(RhinoEngine.java:567)
	... 37 more
[2015-12-15 20:38:32,848]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:32,848+0530]
[2015-12-15 20:38:32,916]  INFO - CarbonAuthenticationUtil 'admin123@carbon.super [-1234]' logged in at [2015-12-15 20:38:32,916+0530]