<b>Fatal error</b>: Call to undefined function ImageCreatetruecolor() in <b>/home/webmfx1/public_html/captchaImage.php</b> on line <b>44</b><br />
Thats what I get when I try to open the file directly - first it downloads as php, but that's the source it's giving.
Not sure if it's case sensative or not but if it is, that'd be why - should be all lowercase. Otherwise there's something not quite right with the gd library on the server you're on I'd guess - that function should work if it's installed.
Edit: Or view below, I swear I must've posted MILLISECONDS before kajasweb