Below is a small PHP script that prints the full path to the directory it is placed in. Copy the code and paste it into a file called fullpath.php. You can then upload the file to the directory where you want to discover its full/true path.. Then point your browser to http://www.your-domain.com/path/to/fullpath.php
Code:
<?php
$dir = dirname(__FILE__);
echo "<p>Full path to this dir: " . $dir . "</p>";
?>