You should not stream at the peak traffic time of the day (your own time zone), such as at noon (the middle of the daylight). Because your Internet Service Provider (ISP) will tend to serve you slower than the usual. You should stream at night or in the morning.
If the audio data fetching hasn't finished but the buffer indicator stops moving, try to pause the audio playing. Then resume the playing after it (the buffer indicator) has made another progress.
If it's completely broken (error), you can refresh the browser and try again.
Try to flush/empty your browser cache. Usually that will have some wanted-impact.
If those four tips above solve nothing, there's download link on every tune.
I'd recommend using latest Chrome or Firefox for desktop. This page uses MP3 format, latest Opera currently supports OGG format and doesn't support MP3.
For mobile browser, only Opera Minidoesn't support multimedia API.