Hmm, maybe that's it. Last night I set the cache size to 200Mb like Moose suggested. Went to watch a little half hr show in HD (720p, Dolby 5.1). Thing ran for about a minute then said 'cache is full' and paused while it filled the cache again. Minute later did the same thing. Maybe I'll just make the cache huge and see what happens.
edit: Streaming the show in standard def, AAC2.0 did seem to work last night, but I'd rather not do that.
SuperNed;390575 wroteI'm guessing the problem isn't your cache. Every now and then things just hang up and I think its on the streaming site's end. I usually just pause it for a full minute or two and it's fine.