ePub converter

I thought to give the ePub converter a try (on a WinXP virtual machine). Is
this the right place to discuss ePub issues? 

I tried to convert a Docbook 5 article to an ePub file and got three
warnings followed by a runtime error: 

C:\Dokumente und
Einstellungen\Boris\Desktop\ruby-1.9.1-p376-i386-mswin32\bin>ruby.exe
"..\..\..\Eigene Dateien\Highscore\docbook-xsl-ns-1.75.2\epub\bin\dbtoepub"
"..\..\article\index.xml"
warning: failed to load external entity "und"
warning: failed to load external entity
"Einstellungen/Boris/Desktop/article/.collapsed.index.xml'"
warning: failed to load external entity "'../../article/index.xml'"
C:/Dokumente und Einstellungen/Boris/Eigene
Dateien/Highscore/docbook-xsl-ns-1.75.2/epub/bin/lib/docbook.rb:122:in
`collapse_docbook': Could not collapse named entites in
..\..\article\index.xml (RuntimeError)

I don't know Ruby. But the warnings make me think that the script has a
problem with blanks in the path and/or something (xmllint?) gets confused
about the slashes (which should be backslashes?). If someone has an idea
what to change in the script I'll give it a try. 

Boris