nullExpression's type was null: ?Expression's type was null: ?
    at 
com.metamatrix.query.optimizer.xml.SourceNodePlannerVisitor.visit(SourceNodePlannerVisitor.java:139)
    at 
com.metamatrix.query.mapping.xml.MappingSourceNode.acceptVisitor(MappingSourceNode.java:31)
    at com.metamatrix.query.mapping.xml.Navigator.visit(Navigator.java:25)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.visit(MappingVisitor.java:37)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.visit(MappingVisitor.java:58)
    at 
com.metamatrix.query.mapping.xml.MappingSourceNode.acceptVisitor(MappingSourceNode.java:31)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.walkChildNodes(MappingVisitor.java:73)
    at com.metamatrix.query.mapping.xml.Navigator.visit(Navigator.java:44)
    at 
com.metamatrix.query.mapping.xml.MappingElement.acceptVisitor(MappingElement.java:48)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.walkChildNodes(MappingVisitor.java:73)
    at com.metamatrix.query.mapping.xml.Navigator.visit(Navigator.java:27)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.visit(MappingVisitor.java:37)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.visit(MappingVisitor.java:43)
    at 
com.metamatrix.query.mapping.xml.MappingSequenceNode.acceptVisitor(MappingSequenceNode.java:20)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.walkChildNodes(MappingVisitor.java:73)
    at com.metamatrix.query.mapping.xml.Navigator.visit(Navigator.java:44)
    at 
com.metamatrix.query.mapping.xml.MappingElement.acceptVisitor(MappingElement.java:48)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.walkChildNodes(MappingVisitor.java:73)
    at com.metamatrix.query.mapping.xml.Navigator.visit(Navigator.java:27)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.visit(MappingVisitor.java:37)
    at 
com.metamatrix.query.mapping.xml.MappingVisitor.visit(MappingVisitor.java:43)
    at 
com.metamatrix.query.mapping.xml.MappingSequenceNode.acceptVisitor(MappingSequenceNode.java:20)