How do I get rid of site-wide error messages in the browser tab?

I've been getting the following warnings across all pages via the browser tab...

<b>Warning</b>: Missing argument 2 for Wiki::wp_title() in <b>/home/nathanbweller/wellerfamily.org/wp-content/plugins/wiki/wiki.php</b> on line <b>298</b>

<b>Warning</b>: Missing argument 3 for Wiki::wp_title() in <b>/home/nathanbweller/wellerfamily.org/wp-content/plugins/wiki/wiki.php</b> on line <b>298</b>
Family Tree - The Weller Family

This results in my site title not appearing. Any help resolving this issue would be a big help. I've uninstalled and reinstalled the wiki plugin and my theme, but that did not solve my problem.