Welcome to the forum.
You can't control playback on both Gizmo and the server. Choose one or the other. Click the top bar in Gizmo to change what you're playing to.
Thank you for the quick reply. Is this because Gizmo doesn't know something changed if I changed the radio station, volume, or switch albums via the HTPC? The way I use it is, I link the zones on the HTPC, press play, then walk around with Gizmo to change the volume at each zone, this causes several crashes. This seems like a very simple application of the software since you cant link the zones using Gizmo.
When I link using the other client (computer downstairs) then happen to be upstairs some time later, I use the HTPC to press stop, change stations, or any other function it crashes. Is this software only meant to be on one computer? I am using one computer as a server, the rest are clients.