[PHP] image generation issues

[Adrian Murphy]

Hi,
I'm using the code in the manual to draw text  on a png.
but Its not working - ImageString() works but not ImageTTFText()
I uploaded arial.ttf from windows to fonts/ folder
Any Ideas:
as a side note: PNG's - any real disadvantage to using them
 instead of gifs - not withstanding the compuserve issue and
old browsers.

the code
button.php
<?php
Header ("Content-type: image/png");
$im = imagecreate (400, 30);
$black = ImageColorAllocate ($im, 0, 0, 0);
$white = ImageColorAllocate ($im, 255, 255, 255);
ImageTTFText ($im, 20, 0, 10, 20, $white, "fonts/arial.ttf","Testing... Omega: 
&#937;");
ImagePng ($im);
ImageDestroy ($im);
?>
and i call it with
<img src="button.php" border="0" alt="">