Order List Suddenly Not Visible from Admin

[kobra]

A link yo to your site might be helpful

[koerce]

Sent you a message. Thanks for the help.

[koerce]

It seems that my problem is similar to this one (albeit, I'm not on 1.3.8). I've re-uploaded orders.php (and the entire admin folder after that) with a fresh copy and there's no change. The admin page is throwing PHP errors to a log but it seems to be happening whenever I visit any admin page:

[29-Sep-2012 21:55:49 UTC] PHP Warning:  constant() [<a href='function.constant'>function.constant</a>]: Couldn't find constant  in [...]/store/zc_admin/includes/functions/admin_access.php on line 38

which throws to

if (constant($result->fields['main_page']) == $page && $result->fields['page_params'] == $page_params) { 

I don't believe this would be the reason because this error just started this afternoon (the store was running yesterday).