[PHP-INSTALL] HTTP 403.1 error Execute Access Forbidden on IIS 5.1

[Pat Johnston]

After installing PHP 5.2.12 on Windows XP and configuring, the test 
phpinfo page fails to execute on IIS 5.1, giving an HTTP 403.1 error - 
Forbidden: Execute Access Forbidden
Internet Information Services
The test web page is under the Inetpub/wwwroot/PHP directory and has 
execute access. The php-cgi.exe also has execute access. I've used .msi 
installers, the Microsoft .wpi installer, and have manually installed 
PHP without success.