Board Thread:Wikia Discussion/@comment-25683568-20150318062713/@comment-25683568-20150711060624

mw.isSubsting isn't provided by the version of Scribunto available on Wikia it seems, so it's trying to call a function that doesn't exist and errors. The version of Scribunto available here is somewhat/quite out of date, so it's missing quite a few things. If you're not planning on substituting Template:Citation needed then you might be able to get away with disabling that if branch and force it to go to the else branch. You might also have some luck trying to see if other wikias have gotten this problem before and how they solve it.