Hi there,
I have the exact same problem than you jeff, and after hours and hours trying to unfold the mysteries of MC17 network, i came to the following results and conclusions :
- I've never been able to make my client's local zone visible from my server computer under the proprietary JRiver Media Network protocol. Curiously, seeing the server's local zone(s) from any client connected to it's library using the access key is working pretty well if this option is enable under "Media Network->Clients Option". And even more strange : the library servers of the clients (witch of course are empty, cause they're just client after all) does appear in the server "Playing from" tree selection. But not the client's zone(s)...
The remaining question is : what's the point? For me, the whole purpose of the "zones" feature, from a network point of vue (i'm not talking about "physical" or hardware zones by using multiple or multichannel sound cards here) should be to allow a centralized management of all the connected audio clients from a single point of the house. The very definition of the multiroom concept in fact. And what's more appropriate to play this central role than the server itself, the machine that hold the files and the library database, do all the indexing job, and allow the automated ripping and tagging of optical medias? Also the only one that actually have to be connected to the internet to do his hard work and share it's resources with the outside.
So curiously, the perfect candidate for this "master" job seem's also to be the only one not allowed to play it... or i'm i missing something?
By the way, and i'm talking to the audiophile people here : living the management to the server, and the server only, provide another great benefit : every cpu / hard drive / network activities needed to browse your music collection from any control point, being an iPad running "My River" or "JRemote", or a notebook connected via WebGizmo, WebRemote, Tremote and so on, actually takes place on the server, not the client itself, even if the client will be the final destination of the chosen audio stream. IMHO, this spare of resources on the client side is far more valuable than any "play file from memory" option, which doesn't work with network resources in the case of MC anyway. Just try to play a song from your network library on your MC client (DLNA or proprietary) with this option activated, and then shutdown your server during playback...
On a side note : The DLNA mode work just fine by setting the server computer as both an DLNA Server and Controller, and the clients computers as a renderers. In this configuration, i'm able to see all my MC DLNA clients on the server and send them an audio stream. But i'm loosing the gapless playback and all the good things provided by the more sophisticated MC proprietary Media Network.
Frustrating (and the wiki dating from MC15 doesn't help)