Error: Unable to send file gibtnochkeinenistauchnurderAnfang.epub.epub. Output buffer contains the following text (typically warnings or errors):

Warning: getimagesize(http://www.letter-factory.com/images/barcode.gif) [function.getimagesize]: failed to open stream: HTTP request failed! in /home/www/ncf1118/html/letter-factory/includes/epub/EPub.php on line 1319