When overriding the DefaultServlet for a given application, the globalXsltFile path need to be relative to Tomcat root. for example: <init-param> <param-name>globalXsltFile</param-name> <param-value>webapps/quercus/WEB-INF/listing.xsl</param-value> </init-param> it would be nice if the path could be relative to the application context.
This has been fixed in trunk and proposed for 6.0.x. I also made the fallback local->context->global->default work as described in the docs
This has been fixed in 6.0.x and will be included in 6.0.25 onwards