Why does generate output on all maps fail with a corba unknown error message?

When generating output on any map, the following error appears in the Error Log view:

org.omg.CORBA.UNKNOWN: --------BEGIN server-side stack trace--------
org.omg.CORBA.UNKNOWN: vmcid: SUN minor code: 202 completed: Maybe at com.sun.corba.se.impl.logging.ORBUtilSystemException.runtimeexception(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.convertThrowableToSystemException(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.handleThrowableDuringServerDispatch(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.handleThrowableDuringServerDispatch(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaServerRequestDispatcherImpl.dispatch(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.handleRequestRequest(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.handleRequest(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.handleInput(Unknown Source)
at com.sun.corba.se.impl.protocol.giopmsgheaders.RequestMessage_1_2.callback(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.handleRequest(Unknown Source)
at com.sun.corba.se.impl.transport.SocketOrChannelConnectionImpl.dispatch(Unknown Source)
at com.sun.corba.se.impl.transport.SocketOrChannelConnectionImpl.doWork(Unknown Source)
at com.sun.corba.se.impl.orbutil.threadpool.ThreadPoolImpl$WorkerThread.performWork(Unknown Source)
at com.sun.corba.se.impl.orbutil.threadpool.ThreadPoolImpl$WorkerThread.run(Unknown Source)
Caused by: java.lang.NullPointerException
at com.ixiasoft.outputgenerator.corba.OutputGeneratorServant.generateDocument(OutputGeneratorServant.java:309)
at com.ixiasoft.outputgenerator.corba.OutputGeneratorServant.generateOutputByteArray(OutputGeneratorServant.java:318)
at com.ixiasoft.outputgenerator.corba.OutputGeneratorServant.generateOutput(OutputGeneratorServant.java:170)
at com.ixiasoft.outputgenerator.corba.OutputGeneratorPOA._invoke(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaServerRequestDispatcherImpl.dispatchToServant(Unknown Source)
... 10 more
--------END server-side stack trace-------- vmcid: SUN minor code: 202 completed: Maybe
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.sun.corba.se.impl.protocol.giopmsgheaders.MessageBase.getSystemException(Unknown Source)
at com.sun.corba.se.impl.protocol.giopmsgheaders.ReplyMessage_1_2.getSystemException(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaMessageMediatorImpl.getSystemExceptionReply(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaClientRequestDispatcherImpl.processResponse(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaClientRequestDispatcherImpl.marshalingComplete(Unknown Source)
at com.sun.corba.se.impl.protocol.CorbaClientDelegateImpl.invoke(Unknown Source)
at org.omg.CORBA.portable.ObjectImpl._invoke(Unknown Source)
at com.ixiasoft.outputgenerator.corba._OutputGeneratorStub.generateOutput(Unknown Source)
at com.ixiasoft.dita.eclipse.actions.runnablewithprogress.RunGenerateDoc.generateDocument(RunGenerateDoc.java:239)
at com.ixiasoft.dita.eclipse.actions.runnablewithprogress.RunGenerateDoc.run(RunGenerateDoc.java:111)at com.ixiasoft.dita.eclipse.jobs.Generat