php3 extension problem

[Anon]

Hello,

I have a php3 script that needs to work on php4

The normal index.php3 is parsed by the server ok but the next link from the index file is something like this;

http://www.domain.com/user/?phpop=new

But this shows up the directory's content.
Anyone know what i must do about this?

The script install help says;
You need PHP3 extensions to the apache web server. PHP4 will also work, but you will need to configure it to understand ".php3" as the proper MIME type

i don't know where and what to do this. please help?

Thanks!
Domenico