all of a sudden we seem to be having problems with any php includes on all of our domains.

Upon simple install of OScommerce - we cannot load the setup or index.php files...
Code:
Warning: main(includes/configure.php): failed to open stream: No such file or directory in /home/username/public_html/shop/includes/application_top.php on line 29

Fatal error: main(): Failed opening required 'includes/configure.php' (include_path='/usr/local/lib/php') in /home/username/public_html/shop/includes/application_top.php on line 29
This is happening on a few if not all of the domains on our server... Just started happening...

HEEELP!