For experts only: Handling bad urls.

Ok! I am desperate and will be very grateful if someone helps me. I want to handle bad urls in some way. In other words, I have the following simple problem: If i try to access an url with a file or directory that does not exist instead of getting the usual error 404 (file not found) sent by the Web Browser (in my case IIS 5.0 on Win2000) i get: "CGI ERROR. CGI Application misbehaved by not returning a complete set of headers.". This is fine. I think what happens is the IIS passes the path as argument to the php interpreter (php.exe, in my case version 4.03), but php.exe doesn't know what to do or returns nothing. What I want to do is to handle this situation in some way. I know I might have to make changes and recompile php.exe. Does anyone can help me with this? I am desperate!!!. THANKS IN ADVANCE. Greetings, Diego. PD. If this simple problem doesn't have a solution, Wouldn't it be a good idea to have this kind of functionality for error handling in the next version of php?