Incorrect error message if a message has no parts

Every input or output message in a soap request must have at least one part, so a message without any parts should be flagged in error. However, if I view the XML for a request (see attached file) where the input message has no parts the only message I see in the lower window is "line -1: null". This is not very informative. It should be more meaningful, such as "message X has no parts".

This was tested in SoapUI 3.6 Beta 2.