When having a link to e.g. http://www.chumba.com/media/Chumbawamba-EnoughIsEnough.mp3 inside an anquor tag ikiwiki seems to parse EnoughIsEnough as WikiWord and breaks the link with that.  As a general rule I would suggest that inside tags there should never be any WikiWord parsing, this is just asking for problems.

You can see an example of the breakage on <http://wiki.debian-community.org/planets/de/> - scroll down to the Chumbawamba entry.