Apache & php problems

There are actually 2 problems, I can't seem to solve on my own. On my test server, running Win98, Apache 1.3.14 (r2), and PHP4.0.4p1, I have tried If I install PHP, using script-alias, it works, for the most part, but 1) If I request a URL like this: http://foo/bar - it finds http://foo/bar.php - why? 2) If I request a non-existent URL that shouldn't normally be handled by PHP, I get the 404 error as expected. However, if I request a non-existent URL that normally would be handled by PHP eg. http://foo/nonexistent.php - I get an internal server error. An entry is added to the Apache log: "Premature end of script headers". Is there a workaround for this? The other, more serious problem arises, when I try to install PHP as a module. When I do that, error redirection works as expected, but my Windows installation goes totally bananas: Some applications will not start at all eg. Mozilla 0.7. Launching of applications via context-sensitive menus will not work (I have an editor attached to right-click menus, so I can open any file easily in that editor). Further: No matter from what application I try to launch other applications via a context-sensitive menu, the host application freezes until I shut down Apache. Has anyone else experienced any of this behavior? For those interested; my httpd.conf is nothing out of the ordinary, scriptaliased, the relevant parts of it are: ScriptAlias /php4/ "D:/php/" AddType application/x-httpd-php4 .php .php4 .php3 .phtml Action application/x-httpd-php4 "/php4/php.exe" and as a module: LoadModule php4_module d:/php/sapi/php4apache.dll AddType application/x-httpd-php .php .php4 .php3 .phtml