Justoverclock That's probably because you've installed the latest version of Flarum (Beta 14) that just got released some days ago.
As @datitisev just said :
This extension hasn't been updated for beta 14 yet
A lot of extensions are dead on the Beta 14 (except the core extensions and some that are getting updated recently and frequently) because the technology behind changed drastically. Thankfully the team are updating one by one each extension to make it compatible to Beta 14.
But no worries they are doing their maximum to update all extensions to Beta 14. Just be patient ^^