Thread:Project:Support desk/PHP Notice: Undefined offset: 0 in /srv/www/vhosts/wiki/extensions/LdapAuthentication.php on line 1208/reply (7)

if you just want to get rid of the messages, then change that line to

$userdn = (isset($info[0]) ? $info[0]["dn"] : "";

But, really, the code you're using looks pretty old. I would upgrade.