包括通过phar档案的firephp

I'm trying to install firephp by using the phar archive. The howto is described here: firephp install

But I've a problem with including the phar file, if tried it this way:

// If using PHAR Archive
set_include_path(get_include_path() . PATH_SEPARATOR . '/Applications/MAMP/firephp/');
require_once('phar://firephp.phar/FirePHP/Init.php');

But the output in my PHP is the following:

Warning: require_once(phar://firephp.phar/FirePHP/Init.php): failed to open stream: phar error: invalid url or non-existent phar "phar://firephp.phar/FirePHP/Init.php" in /Applications/MAMP/htdocs/test.php on line 21

Fatal error: require_once(): Failed opening required 'phar://firephp.phar/FirePHP/Init.php' (include_path='.:/Applications/MAMP/bin/php/php5.4.10/lib/php:/Applications/MAMP/firephp/') in /Applications/MAMP/htdocs/test.php on line 21

As you can see the "include path" is set to the right place, here you can see my folder structure:

Where is the problem!?

Little information: In the german Version of MAC OS the Folder Applications is automatically called "Programme". but the path is always /Applications/. If you're using the terminal it will always show "Applications"