http://bugs.winehq.org/show_bug.cgi?id=16239
--- Comment #14 from Mike Kaplinskiy mike.kaplinskiy@gmail.com 2010-02-04 20:34:05 --- Seems the problem is that the installer requests an ancient version of msxml (ie before 3), which means it expects XSLT Pattern matching and not XPath. (Hooray for reading msdn instead of blaming microsoft...)
Wine's msxml doesn't have xsl pattern implemented, and it doesn't seem like libxml2 nor libxslt support them (the latter does, but only with xslt transformations). From the short description http://saxon.sourceforge.net/saxon6.5.3/patterns.html it looks very similar to xpath but seems to be completely namespace unaware.
We would probably want to just write a converter to xpath.