Fatal error: require_once() [function.require]: Failed opening required

I would go through the following assumptions debugging this,

1. The file doesn't exist.
2. The ROOT_PATH is incorrectly set.
3. The current working directory isn't what is expected, so if ROOT_PATH is relative, it's breaking the full path.

If none of the above is the case, I'm not sure.

Some libraries must be installed into a directory that is listed in PHP's library path. In these situations you have a few options:

• Install the library into a directory searched by PHP by default (e.g., /usr/share/php).
• Update the include path using set_include_path without overwriting the old path (use get_include_path in combination with PATH_SEPARATOR).

ROOT_PATH is not defined in your script. This should be a defined constant with the value of your root path.

Check it if it is defined or not.

if (defined('ROOT_PATH')) { echo 'Defined';} else { echo 'Not defined'; } 

It is not defined.

If it was defined then your error message will contain the value of defined constant since it contains the constant itself in error.

Define in your script.

define('ROOT_PATH',$_SERVER['DOCUMENT_ROOT']); //an example 

OR you have forgot to include the configuration file in which these constant are defined.

Just do an echo of the whole path you pass to the require_once function and carefully check if there is something wrong with it :

echo ROOT_PATH . "/lib/confs/Conf.php"; 

I ran into this problem today. I found the answer. PHP Bug #23392

Basically you have to install the Pear OLE extension.

pear install OLE