I was already at 8/10 completed quests (with the last one giving me a "you're not on a quest" error when I tried to complete it, even though it rewarded me appropriately). When I went to the 9th quest, it gave me the following error:

Fatal error: Call to undefined method Controller_Quests::wizard() in /www/subeta.net/include/mvc/controllers/Controller_Quests.php on line 99

And now I can't start any Wizard quests anymore!

I use Mozilla Firefox on a Windows 8.1 notebook.

nvm

It has been solved, thank you!