Thread:Extension talk:GoogleLogin/Internal error " WEBROOT /mediawiki-1.22.2/includes/htmlform/HTMLForm.php: HTMLForm: no submit callback provided. Use setSubmitCallback() to set one."/reply (21)

P.S.: Is there a reason why you set your article path to index.php?title=$1 ??? This seems to is the problem why the Create of an account won't work :/ I'm working on it, but if you haven't a good reason why to set $wgArticlePath, then maybe you can remove it :D

Or, if you don't set it manually, then you can change it to "$wgScript/$1". In my tests, then all works fine.