php include_once failing despite existence of file and 777 permissions

[calmshot]

php include_once is failing for me with the "failed to open stream: No such file or directory" message, despite the existence of the file it is complaining about, and chmod'ing to 777 in order to try to mitigate the problem.warning: include_once() [function.include]: Failed opening '../i_utility/WCHelper.php' for inclusion (include_path='.:/usr/share/pear:/var/www/html/we_/') in /var/www/i_/php/w_corner/modules/i_ers/i_ers.module on line 6.From the command line I can cd to the directory containing the source code file (/var/www/i_/php/w_corner/modules/i_ers), and I can ls the file about which php complains "no such": ../i_utility/WCHelper.phpIndeed, I can do the above after su'ing to the apache user, and can even touch the file and see its last modified timestamp changed:\[code\]-bash-3.2$ whoamiapache-bash-3.2$ cd /var/www/i_/php/w_corner/modules/i_ers-bash-3.2$ ls -l ../i_utility/WCHelper.php-rwxrwxrwx 1 root root 32112 Sep 14 09:49 ../i_utility/WCHelper.php-bash-3.2$ touch ../i_utility/WCHelper.php-bash-3.2$ ls -l ../i_utility/WCHelper.php-rwxrwxrwx 1 root root 32112 Sep 27 17:08 ../i_utility/WCHelper.php\[/code\]In light of all of the above, what could be causing PHP's include_once to fail under these circumstances?