GD library images not displaying

Hi, I am running Apache 2.0 with PHP 4.2.11 on Windows XP. I installed php_gd2.dll by uncommenting extension=php_gd2.dll and making sure that the file was in my extension_dir. I restarted Apache and didn't get an error, so assumed it was working. When I run my example code: <?php $im = imagecreatetruecolor (300, 200); $black = imagecolorallocate ($im, 0, 0, 0); $white = imagecolorallocate ($im, 255, 255, 255); imagefilledrectangle($im,0,0,399,99,$white); imagerectangle($im,20,20,250,190,$black); header ("Content-type: image/png"); imagepng ($im); ?> I get the following error: Fatal error: Call to undefined function: imagecreatetruecolor() in imagetest.php on line 2 This code works on other servers, so where have I gone wrong in my installation of GD? Thanks in advance, Ross