Error loading stylesheet

[Ian Gregory]

My homepage has a link to the FOAF.Vix view of my FOAF file:

http://foaf-visualizer.org/?uri=http://www.zenatode.org.uk/foaf.rdf

This renders fine in Safari but I got a complaint from a friend who says all he can see is a pale yellow page containing the following error:

Error loading stylesheet: An XSLT stylesheet does not have an XML mimetype:

http://foaf-visualizer.org/fvx-html.xsl?v=1.0

He is using Iceweasel 3.5.16 on Debian Squeeze

Any ideas?