I'm getting a little frustrated.  I'm not sure what I'm doing wrong. Why does this work?  

var messageTest = opensocial.newMessage("Test this.");

opensocial.requestShareApp(userID, messageTest , function(){
   alert('sent application invite');
  }
);

And this doesn't.... 

var messageTest = opensocial.newMessage("Test this.");

opensocial.requestSendMessage(userID, messageTest , function(){
   alert('sent application invite');
  }
);

Please help

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nm, This is fixed. I need to use paramaters in the message. Ex:

var params = {};
params[opensocial.Message.Field.TITLE]= 'HI';
params[opensocial.Message.Field.TYPE] = opensocial.Message.Type.PRIVATE_MESSAGE;