<? $success = @include_once(dirname(__FILE__)."/elem/config.inc.php");
if (!$success) { echo "Include failed"; } ?>

А это?

<?php

  function getPath() {
       
     // get position of current file
     $path = $GLOBALS["PATH_INFO"];
     // save a few nanaseconds, has this been done before,
     // has the global variable been set ?
     if (!isset($definedPath)) {
        // is file in root already ?
        if (strrpos($path,"/")!=0) {
           // there is probably a quicker way to count
         // the "/"s in the path
          $path=explode("/",$path);
           $s="";
         for ($i=0;$i<count($path)-1;$i++) {
              if ($path[$i]!="") {
                 // add the number of "../"s required
                 $s.="../";
            }
           }
           // declare a global variable so you dont have to
           // do this again, and return the variable
           global $definedPath;
          $definedPath=$s;
           return $definedPath;
        }
    } else {
        // just return what it worked out before, function
        // only really runs once
        return $definedPath;
     }
  }
   
  include getPath() . "my_include_path/header.inc";
  include getPath() . "includes/somethingelse.inc";
  //above file is at mydomain.com/includes/somethingelse.inc
  include getPath() . "includes/footer.inc";

?>