What's the exact revision of Jamcast? They brought out a new one mid October then released some Hot Fixes a few days later. I'll check at home tonight which one I'm using, but I haven't had any problems like you describe.
Is it only with Spotify or is it with streaming media from your PC? And with Spotify, does using your PC Speakers fail...next time it fails turn up the volume on your PC and see if it is still playing there. If it has stopped working then it is Spotify or networking rather than jamcast.
The support forums on the Jamcast site are pretty good, they get back to you quite quickly. A quick look on their support forums gives mention of the service needing around 1.5Mb/s to run properly...if your wireless connection drops below that for some reason you might get a glitch. Could you test it using a cabled connection to your network and see if it still has the same problem?
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