Problems writing a translator

[I hope this doesn't come through twice; I wasn't subscribed the first time I sent]

Hi all,

I'm trying to understand the Hurd by writing my first  translator, and got a bit stuck. I'd appreciate some help. My source is  here: https://github.com/iamleeg/machoo

What  I'm trying to achieve is that the out parameter of the message_send  operation is a port on which the client can send the same message, to  get the ball rolling I'm trying to get it to return itself (so if the  client sends a message to the returned port, it is messaging the same  server).

The current behaviour is that the server starts up  correctly when registered with settrans, and the client connects and  sends the message. The message is correctly handled by the demuxer, and  my handler routine is called. However the return value on the client  side is -300, MIG_TYPE_ERROR. What have I done wrong, here?

Thanks for your help,

Graham.