File Upload Error

Hello,

I'm trying to implement a simple file upload in Web Dynpro and I get the following error upon a web dynpro action after I select a file. Does anyone know what this error means?

com.sap.tc.webdynpro.services.sal.util.cache.WDResourceNotFoundException: Object could not be found in cache, key is null! at com.sap.tc.webdynpro.services.sal.util.cache.WebResourceCache.getResource(WebResourceCache.java:207) at com.sap.tc.webdynpro.services.sal.util.cache.WebResourceCache.getResource(WebResourceCache.java:229) at com.sap.tc.webdynpro.serverimpl.defaultimpl.datatransport.DataTransportFactory.getOutputMassDatasource(DataTransportFactory.java:78) at com.sap.tc.webdynpro.services.sal.datatransport.core.InternalMassDataTransport.getOutputMassDatasource(InternalMassDataTransport.java:41) at com.sap.tc.webdynpro.progmodel.context.ModifiableBinaryType.parse(ModifiableBinaryType.java:101) at com.sap.tc.webdynpro.clientserver.data.DataContainer.doParse(DataContainer.java:1346) at com.sap.tc.webdynpro.clientserver.data.DataContainer.validatePendingUserInput(DataContainer.java:1256) at com.sap.tc.webdynpro.clientserver.data.DataContainer.validatePendingUserInput(DataContainer.java:598) at com.sap.tc.webdynpro.clientserver.cal.ClientComponent.validate(ClientComponent.java:623) at com.sap.tc.webdynpro.clientserver.cal.ClientApplication.validate(ClientApplication.java:674) at com.sap.tc.webdynpro.clientserver.task.WebDynproMainTask.transportData(WebDynproMainTask.java:649) at com.sap.tc.webdynpro.clientserver.task.WebDynproMainTask.execute(WebDynproMainTask.java:581) at com.sap.tc.webdynpro.clientserver.cal.AbstractClient.executeTasks(AbstractClient.java:57) at com.sap.tc.webdynpro.clientserver.cal.ClientManager.doProcessing(ClientManager.java:251) at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doWebDynproProcessing(DispatcherServlet.java:139) at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doContent(DispatcherServlet.java:101) at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doPost(DispatcherServlet.java:45) at javax.servlet.http.HttpServlet.service(HttpServlet.java:760) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.runServlet(HttpHandlerImpl.java:385) at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.handleRequest(HttpHandlerImpl.java:263) at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:337) at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:315) at com.sap.engine.services.httpserver.server.RequestAnalizer.invokeWebContainer(RequestAnalizer.java:815) at com.sap.engine.services.httpserver.server.RequestAnalizer.handle(RequestAnalizer.java:238) at com.sap.engine.services.httpserver.server.Client.handle(Client.java:92) at com.sap.engine.services.httpserver.server.Processor.request(Processor.java:147) at com.sap.engine.core.service630.context.cluster.session.ApplicationSessionMessageListener.process(ApplicationSessionMessageListener.java:37) at com.sap.engine.core.cluster.impl6.session.UnorderedChannel$MessageRunner.run(UnorderedChannel.java:71) at com.sap.engine.core.thread.impl3.ActionObject.run(ActionObject.java:37) at java.security.AccessController.doPrivileged(Native Method) at com.sap.engine.core.thread.impl3.SingleThread.execute(SingleThread.java:94) at com.sap.engine.core.thread.impl3.SingleThread.run(SingleThread.java:151)