Apache is not parsing my php...sometimes...

I've got an exceedingly wierd issue. I'm running a default installation of Linux Slackware 8.0. I've got the apache and mod_php modules installed. If I access my php document as follows, everything is parsed correctly: http://www.example.net/mypage.php However, if I access the page with the following, the code is not parsed and the php is placed in my html as plain text (bad because I have MySQL passwords in there): http://www.example.net/mypage Is anyone familiar with this problem. Is it a httpd config problem, perhaps a problem with how the php module was configured? Thanks in advance!