loading php_gd2.dll

Hi. I'm having difficulty getting the php_gd2.dll to load. Running W2K server, IIS 5.0, PHP 4.3.1. I've modified the php.ini file and set my extensions directory to C:\PHP and I've uncommented extension=php_gd2.dll. When I do this, and attempt to load the php test page, my browser attempts to load the page forever, with no success. If I then comment it back out, the page loads, but of course without the dll. I've tried to uncomment and load a couple of other dlls, same result. And those I attempt to load are in the C:\PHP directory where I assume they should be. Anybody have any suggestions? Thanks. Brent