Exporting models to BPMN 2.0 results in a "IRJH0012E" error

When you export models from RSA to the BPM 2.0 format, the export process ends unexpectedly with a message stating that the Export did not complete.
If you then look at the errors traced in the Error Log view, you will see the following message:
IRJH0012E Transformation "Exporter" aborted during its execution; descriptor id="com.ibm.xtools.bpmn2.exporter.ExporterTransformation"

The matching exception stack trace is:

java.lang.IllegalArgumentException: local part cannot be "null" when creating a QName
at javax.xml.namespace.QName.<init>(Unknown Source)
at javax.xml.namespace.QName.<init>(Unknown Source)
at com.ibm.xtools.bpmn2.exporter.internal.transforms.util.BPMNExporterUtil.getQName(Unknown Source)
at com.ibm.xtools.bpmn2.exporter.internal.rules.DataInputAssociationSourceRule.execute(Unknown Source)
at com.ibm.xtools.transform.authoring.CustomRule.copy(Unknown Source)
at com.ibm.xtools.transform.authoring.CustomRule.createTarget(Unknown Source)
at com.ibm.xtools.transform.core.AbstractRule.execute(Unknown Source)
at com.ibm.xtools.transform.authoring.TransactionalRule.access$0(Unknown Source)
at com.ibm.xtools.transform.authoring.TransactionalRule$1.doExecute(Unknown Source)
at org.eclipse.emf.workspace.AbstractEMFOperation.execute(Unknown Source)
at com.ibm.xtools.transform.authoring.TransactionalRule.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.internalExecute(Unknown Source)
at com.ibm.xtools.transform.core.Transform$1.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInWorkspaceRunnable(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.internalExecute(Unknown Source)
at com.ibm.xtools.transform.core.Transform$1.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInWorkspaceRunnable(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.internalExecute(Unknown Source)
at com.ibm.xtools.transform.core.Transform$1.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInWorkspaceRunnable(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.internalExecute(Unknown Source)
at com.ibm.xtools.transform.core.Transform$1.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInWorkspaceRunnable(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.internalExecute(Unknown Source)
at com.ibm.xtools.transform.core.Transform$1.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInWorkspaceRunnable(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.internalExecute(Unknown Source)
at com.ibm.xtools.transform.core.Transform$1.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInWorkspaceRunnable(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.transform.core.Transform.internalExecute(Unknown Source)
at com.ibm.xtools.transform.core.Transform$1.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper$1.run(Unknown Source)
at org.eclipse.gmf.runtime.emf.core.internal.domain.MSLEditingDomain.runInUndoInterval(Unknown Source)
at org.eclipse.gmf.runtime.emf.core.internal.domain.MSLEditingDomain.runInUndoInterval(Unknown Source)
at org.eclipse.gmf.runtime.emf.core.util.OperationUtil.runInUndoInterval(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInUndoInterval(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper$4.run(Unknown Source)
at org.eclipse.core.internal.resources.Workspace.run(Unknown Source)
at org.eclipse.core.internal.resources.Workspace.run(Unknown Source)
at com.ibm.xtools.transform.core.internal.engine.TransformRunHelper.runInWorkspaceRunnable(Unknown Source)
at com.ibm.xtools.transform.core.Transform.execute(Unknown Source)
at com.ibm.xtools.bpmn2.exporter.internal.wizard.BPMN2ExportWizard.performExport(Unknown Source)
at com.ibm.xtools.bpmn2.exporter.internal.wizard.BPMN2ExportWizard$4.run(Unknown Source)
at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(Unknown Source)

This error happens when the model to export is not valid and contains missing references.

To verify that this is in fact the problem you are experiencing, validate the models you want to export, before actually exporting them and check whether you have validation errors similar to this one:
The feature 'message' of 'Collection::Collection::<MessageFlow>' has a reference to '' which cannot be found.

SOLUTION

1. Validate your model
   
   
2. Fix every error related to a missing reference, either by removing the invalid reference or by replacing it with a valid one
   
   
3. Validate your model until there are no more validation errors
   
   
4. Export the model to BPMN