CGI error?

Hello everyone, This may be a simple answer, but ive looked through php.net and apache.org. I have both ISS5 and Apache on my windows 2000 machine. IIS5 has a setting under the extention mappings that let the server check if a file exists before sending it to the php executable...that way I get a 404 not found error instead of CGI Error: ect... Is there a setting similar to this that I can set in apache or php. I simply want a 404 errordocument to be shown if a php file is not on my server instead of the current CGI Error (in apache). Thanks for any help! ~Jeff