> Yes, that's a known bug which came up a little while ago. It is fixed in
> the drafts (XML Spy regarded
> an extension of all as legal but it turns out it isn't!).

Mono Web Services Description Language Utility
Error: XmlSchema error:
Ambiguous element label was detected:
Related schema item SourceUri:
   Line 91, Position 11.

Mono complains about your drafts, but I don't see why as there is only one
stylesheet element.  Removing the stylesheet reference, it then goes on to
complain about other ambiguous labels.

Possibly to do with the extension?