Cannot get php_http.dll to work

Hi, I have tried umpteen times to get this to work by PHP still insists that it cannot find the 'HttpRequest' Class. Using PHP 5.2.3 Downloaded latest version of php_http.dll, for PHP 5.2.x from the PECL website Installed it in the D:\PHP\ext directory Added 'extension=php_http.dll' to the php.ini file made sure the extension_dir is set to 'D:\PHP' Restarted Apache..even restarted the entire computer And with all of this it's still not recognising this Class. I've searched all over the net but to no avail...pretty much every answer refers to adding the extension line to the .ini file. Can anyone advise what else I may be able to do? Thanks Alexis