If you are using Loadmodule, it looks like you are going down the SAPI route. I much prefer to use the CGI route on a low-load server for 1.3.2x. Try this in httpd.conf:
ScriptAlias /php/ "c:/php4/"
(tell is where php lives)
AddType application/x-httpd-php .php3
AddType application/x-httpd-php .php
(tell it what type of thing a .php file is)
Action application/x-httpd-php "/php/php.exe"
(tell it what to do with this type ie run php.exe in (scriptaliesed) php location /php/ which expands to C:/php4)
The take out the loadmodule stuff as you don;t need it for CGI.
HTH
David.