Hello Stefan,
this is my xml up to line 9:

<?xml version="1.0" encoding="iso-8859-1" ?>
<!-- 
 Old reference
<!DOCTYPE rem:requirementsProject SYSTEM "C:\tmp\rem\foo.dtd">
-->
<!--
<!DOCTYPE rem:requirementsProject SYSTEM "file:C:\\Desarrollo\\pythontes
ts\lxml\foo.dtd">
-->
<!DOCTYPE rem:requirementsProject SYSTEM "C:\Desarrollo\pythontests\lxml\foo.dtd">


I omitted the commented lines in my first snippet.

PD: I'm sorry I sent the response straight to you and missed the mailing list.