Important note about performing remote transactional reads (introduced in MSMQ 4.0) - both the machine reading the queue and the machine hosting the queue have to be running MSMQ 4.0, not just the reader.

929788 Error message when you perform a transactional remote receive that invokes an external transaction from a down-level client: "0x800706D9 - "There are no more endpoints available from the endpoint mapper""