newbie-Apache Install on XP

I am attempting to set up PHP 4.2.1 on WinXP Home with Apache 2.0.39 already installed and running. After following instructions in the install file to move dll's into appropriate locations and edit php.ini accordingly, I continuosly receive an error when attempting to start Apache. Apache will not start and I find the following error message in the Application Event Error log: Apache.exe: module "c:\php4build\snap\sapi\apache2filter\sapi_apache2.c" is not compatible with this version of Apache. and the System Error from the system log: The Apache2 service terminated with service-specific error 1 (0x1). Is there a configuration file pointing to this file? I can't find the file anywhere on the system... Any ideas???? Thanks, Brandon