When I install PHP 4.2.1 as a SAPI module to Apache 2.0.39 I haven't had any problems with any of my scripts until I was going to log the IP of my visitors. So I used the fallowing 'script' to get the IP's... <?
echo 'REMOTE_ADDR:' . getenv(REMOTE_ADDR);
echo 'HTTP_X_FORWARDED_FOR:' . $_ENV['HTTP_X_FORWARDED_FOR'];
?>

It won't return anything at all just a empty string...
So I tried to install PHP with the CGI support using:

#=============================================

ScriptAlias /php/ "c:/php/"
AddType application/x-httpd-php .php
Action application/x-httpd-php "/php/php.exe"
#=============================================

instead of (Conf. for SAPI):

#=============================================

LoadModule php4_module c:/php/sapi/php4apache2.dll
AddType application/x-httpd-php .php
#=============================================

Now when I use the same 'script' as above I get both the REMOTE_ADDR and the HTTP_X_FORWARDED_FOR correct...