Configuring Scripto with MediaWiki

I have found out how to enable error messages help from Reclaim Hosting. Now I have found that the error issue is with MediaWiki. I have tried to locate the API URL so as to be able to configure Scripto. However with no success. I have use variations of this URL http://yolocountyhistory.com/wiki/index.php. Where do I locate the correct API/URL, or is there something else I am missing?

exception 'Omeka_Plugin_Installer_Exception' with message 'Invalid MediaWiki API URL' in /home/yolocoun/public_html/plugins/Scripto/ScriptoPlugin.php:264

Most likely, it will be http://yolocountyhistory.com/wiki/api.php

Here is the documentation from MediaWiki:
https://www.mediawiki.org/wiki/API:Main_page