IDoc-> PI->SOAP Webservice mapping null pointer error

Hi Experts,

I am building a message mapping from IDoc to SOAP Webservice.  I couldn't pass the message mapping step.  I loaded the IDoc just fine on the left side.  But when I try to load the webservice structure on the right side, it gave me nullpointerexception error (see the attached file).  Any help would be greatly appreciated and awarded.

Thanks,

Joanna