Thanks for the reply.
1. No errors, just no Settings tab at all. When I open scp/admin.php I have tabs for Tickets, Knowledge Base, Directory and My Account. Tickets appears to work, Knowledge Base allows me to add new canned responses, Directory allows me to see users, but not add/remove and My Account has sections for My Profile, Preferences and Change Password.
2. If I open open.php or index.php I get the same thing. That is a screen that says Authentication Required and prompts for E-Mail and Ticket ID. If I enter a valid email and ticket id then I can get in, but otherwise can't do anything. Clicking on Home, New Ticket or Ticket Status at the top results in exactly the same thing. The URL in the browser changes to what it should be.