Here is what I trying to do:
I want any http request to a particular directory to run a static PHP script. The static PHP script does not reside in the Document_Root, but another directory on the server.
Here is the RewriteRule in my .htacess file in directory 'test':
RewriteRule ^(.+)$ /phpDir/myScript.php [L]
The 'test' directory is empty except for the .htaccess file.
You will have to check the apache error logs for the exact error message as there are many reasons regarding the 403 and 404 error message. You will find the apache error logs at /usr/local/apache/logs/error_logs