Which PHP version are you using? I think that you can't use version 4.3.3 with Abyss Web Server and therefor I'm using version 4.3.2. Aprelium have a copy of the Windows installer here:
Go into your Abyss Web Server console, click "Server Configuration", then "Advanced", then "CGI Parameters" and finally click the "Add" button under "User CGI Environment Variables". In the name field ...