pw44, I tested the link and it does not work. Don't know why, but there is probably something different about that m3u URL than other m3u URLs. Might be some server settings that is different (content-type) or difference in the file itself. I'm really just blurting out ideas here...
While it is bad that this URL doesn't work, I'm not sure if we will do anything to support it, as this is a xine-lib thing. It depends on what the problem is and if we can do simple changes to fix it. If you could identify any differences between a working URL and a non-working URL, we might be able to consider a fix for it.