I downloaded some documentation in docbook form from KDE's site and tried to produce a pdf from it. This didn't work because it referenced kdex.dtd and couldn't find it. The file is on my system, but seems not be integrated into Debian's docbook machinery. I tried various things like hardcoding the complete path, but apparently other files need to be set up to, and aren't. What do I need to do so I can use the document?