Resolution:
Answer:  The establishment of a SmartSockets connection is a multi-handshake process. First is establishment of the low-level TCP socket, next the SmartSockets conn layer followed by the publish/subscribe (routing) layer, and then (in the case of RTserver-to-RTserver connections) the new RTserver gets 'primed' with all the necessary cloud topology and subscription information it needs to be a functional component of a SmartSockets cloud. If this final step fails the "priming failed" message will be thrown.

Question: What would cause this failure?
Answer: A timeout or other loss of connection. The timeout could be the result of a loaded network, or perhaps a large amount of traffic if several RTservers are all trying to get started simultaneously. (A good practice is to stagger multiple RTserver launches)