Fatal Error when loggin in??

Haven’t worked on my site for about a week, and now when I try to login at WP-admin I get this error and cannot get to the admin dashboard:

Fatal error: require_once() [function.require]: Failed opening required ‘/hermes/bosweb26b/b2455/ipg.wunderwomanca/website3/wp-admin/includes/admin.php’ (include_path=’.:/usr/local/lib/php-5.2.17/lib/php’) in /hermes/bosweb26b/b2455/ipg.wunderwomanca/website3/wp-admin/admin.php on line 64

Ckeced out the admin.php folder and line 64 looks correct. Not sure what the INCLUDES folder is that’s between /wp-admin/includes/admin.php Could it be something with that folder? Still new to this so any help would be appreciated!