Web Service no longer working after Upgrading to Peopletools 8.51

We have recently upgraded from tools 8.48 to 8.51.  We have a web service that was developed in 8.48 and was being provided to/consumed by a 3rd party application.  Since the upgrade, the service is no longer working.  This is a fairly straight forward web service that accepts an operator ID, performs a validation in an application package and responds with a message indicating whether or not the ID is valid.  When I attempt to test the service using Sendmaster, I am receiving the following output and error message:

Message-ID: <26112497.1315509146512.JavaMail.PHSPSTWEB6$@PHSPSTWEB6>
Date: Thu, 8 Sep 2011 15:12:26 -0400 (EDT)
Mime-Version: 1.0
Content-Type: multipart/related;