php not activated on my computer.

Dear sirs, I downloaded the php binary version 4.2.3 also php installer. My Computer OS is Win98 with PWS installed. I installed both automatically and manually excatly the way of installation guide.But both I had the same problem: HTTP Error 403 403.1 Forbidden: Execute Access Forbidden This error can be caused if you try to execute a CGI, ISAPI, or other executable program from a directory that does not allow programs to be executed. Please contact the Web server's administrator if the problem persists. would you please tell where is the problem. Many thanks Nikou