Thanks Chuck, I was able to enter the full path for the arcade mod in the navbar template and it fixed that one link. It was an easy fix because it launches a php file and I just entered the full path as http://www.domainname.com/arcade.php
and the link in the navbar works fine now.
Note: I understand this is not a PhotoPost question. You don't have to respond, but if you do, I would be grateful.