AGB 2.4.1 Image Verification Problem

I recently installed the guestbook on a test server but i can't post any entries, because the image verification produces unreadable images.

This is a sample of the output:

What did i do wrong?

There are probably some problems with FreeType.

Disable TTF in the ouptut script image.php

<?php
$include_path = dirname(__FILE__);
include_once $include_path."/admin/config.inc.php";
include_once $include_path."/lib/$DB_CLASS";
include_once $include_path."/lib/captcha.class.php";

if (USE_CAPTCHA) {
	if (isset($_GET['id']) && !empty($_GET['id'])) {
		$_GET['id'] = trim($_GET['id']);
		$id = addslashes($_GET['id']);
		$expired = time() - 2*3600;
		$db = new gbook_sql();
		$db->connect();
		$db->query("DELETE FROM {$GB_TBL["cap"]} WHERE timestamp < $expired");
		$res = $db->query("SELECT * FROM {$GB_TBL["cap"]} WHERE session_id='$id' LIMIT 1");
		$result = $db->fetch_array($res);
		if (isset($result['validate_key'])) {
			$imageType = "";			
			include_once $include_path."/lib/bitmapimagetext.class.php";
			$img = new BitmapImageText();
			$img->setText($result['validate_key']);
			$img->setBackgroundColors(array("EEEEEE", "F2F3D3", "F5EAEA", "E4F3EE", "EEE4F3", "FFE6E6"));
			$img->setTextColors(array("000000", "FD130A", "0A1BFD", "149703", "486C66", "870DC3", "D78406", "105243"));
			if (!empty($imageType)) {
				$img->getImage($imageType);
			} else {
				$img->getImage();
			}
			exit();
		}
	}
}

SimpleCaptcha::createPixel();

?>

Can you post the gd version und os which is installed on your testserver?

thanks

Thanks for your help, your solution worked!

Server Info:
Linux Server
Apache 2.0.54
PHP 5.0.4 + Zend 2.0.4-dev
GD Version 2.0.28
FreeType Version 2.1.10

When I use the script above I get a X at the image...no image but a sign that there is no image. When I than put back the older version image.php I see again the image of captcha but all above each other...not to read.

PHP Version 4.3.11
GD Support enabled
GD Version bundled (2.0.28 compatible)
FreeType Support enabled
FreeType Linkage with freetype
GIF Read Support enabled
GIF Create Support enabled
JPG Support enabled
PNG Support enabled
WBMP Support enabled
XBM Support enabled
Apache/1.3.34 Ben-SSL/1.57 (Unix) FrontPage/5.0.2.2510 PHP/4.3.11 mod_jk/1.2.2

In the beginning it did worked all.

Tanks