MessageProcessor doesn't deal with XML and hence doesn't care what your XML tags are called.
There is a MessageProcessorApp sample app, but it doesn't care what the parent tag is called as long as each message tag is called <message>. If I change <messages> to <geomessages> or even <foo>, it works fine. Is it possible that your start tag is called <geomessages> but your end tag is called something else? I see no messages when that is the case.
By the way, can you please explain what the Military Template toolbox is?