Since I spent some time in finding the source of the error, I would like to leave a comment here - maybe it helps other users saving debugging time.
After including the extension in our wiki we had an error message:
XML-Verarbeitungsfehler: XML- oder Text-Deklaration nicht am Beginn der Entität
.
When we looked at the HTML-source code of the page generated by MW, we discovered, that the first line of the page was empty. We checked the other extensions in our wiki, and found out that the error was caused by an extension which started with \nl<?php
rather than with <?php
. We removed the \nl
and everything worked fine.
This post was posted by Kappa~mediawikiwiki, but signed as Kappa.