JSW wrote:Any other ideas?
I know it's sounds basic but check your network hardware, you may have a flaky cable or switch (I assume all of these boxes are not connected directly to your router if they are really check your cables).
Roksbox won't degrade gracefully like Netflix so if your bitrate is to high for your hardware you might have problems. This is possible with 100mb switches and high bitrate encodes.
I think Wild has the best idea for starters, take one known good box and move it to trouble spots.