Exception encountered, of type &quot;Error&quot;<br />
[8fa81c85817d6b6d64b446be] /wiki/index.php?action=pdfbook&amp;title=Category%3APublication   Error from line 18 of /var/www/mondotheque.be/wiki/extensions/PdfBook/PdfBook.hooks.php: Call to undefined function wfMsg()<br />
Backtrace:<br />
#0 /var/www/mondotheque.be/wiki/includes/Hooks.php(195): PdfBookHooks::onUnknownAction()<br />
#1 /var/www/mondotheque.be/wiki/includes/MediaWiki.php(507): Hooks::run()<br />
#2 /var/www/mondotheque.be/wiki/includes/MediaWiki.php(288): MediaWiki-&gt;performAction()<br />
#3 /var/www/mondotheque.be/wiki/includes/MediaWiki.php(745): MediaWiki-&gt;performRequest()<br />
#4 /var/www/mondotheque.be/wiki/includes/MediaWiki.php(519): MediaWiki-&gt;main()<br />
#5 /var/www/mondotheque.be/wiki/index.php(43): MediaWiki-&gt;run()<br />
#6 {main}<br />