problem running php4.0.6 and apache1.3.22 on winXP

Hi, I installed php4.0.6 and apache 1.3.22 (as a service) on windows XP and followed the instructions to configure the httpd.conf file to load php as an apache module (including the AddModule mod_php4.c instruction). I have also copied the php4ts.dll file to the windows/system32 directory, but when I try to run any php script with the browser, I only get a blank page. It seems that apache doesn't send the script for interpretation by php (even though apache is loading the php module). Can anyone tell me what's wrong? Thanks, Rui