I have been getting constant disconnects from multiplayer sessions with the PMDG 777 After a few minutes I get the "Host has cancelled session, would you like to continue flying single player" Is this normal? Is the PMDG 777 not multiplayer compatible? Happens all the time.

I am not aware of any multi-player capability in any PMDG product. PMDG has discussed this in other threads, and although they are interested in doing this the state of the art in networking FSX is not compatible with PMDG products due to their high level of customization.