Understanding behavior of 'directories below files'

I'm a system administrator who's dabbled a bit in PHP, but am not very experienced in it. My PHP developer came to me with a behavior which neither of us can understand. If you go to this URL, you'll get a broken version of the main home page on our site: http://www.hcpartnership.org/index.php/search . We can't understand this, because 'index.php' is a file, not a directory. (The correct web page is just at http://www.hcpartnership.org/index.php.) Here's another example: http://www.hcpartnership.org/path_test.php/search : does not generate a 404 error http://www.hcpartnership.org/path_test.html/search : generates a 404 error This is despite the fact that both of these two files are empty: www:/var/www/hcpartnership/htdocs# ls -l path* -rw-r--r-- 1 rmcpeak wwwadmin 0 Jun 25 10:09 path_test.html -rw-r--r-- 1 rmcpeak wwwadmin 0 Jun 25 10:10 path_test.php www:/var/www/hcpartnership/htdocs# Can anyone explain to me why this is happening? Is this a danger? Can this be turned off? Is this controlled in the .php code, in the php.ini file or in the Apache configuration, or elsewhere? We didn't even know how to describe this problem well, so our searches of the archives of this mailing list and Google weren't successful. Let me know if we overlooked something. Thanks so much for your suggestions and thoughts. -Kevin Zembower ----- E. Kevin Zembower Unix Administrator Johns Hopkins University/Center for Communications Programs 111 Market Place, Suite 310 Baltimore, MD 21202 410-659-6139