foutmelding pdf

Ik gebruik sinds kort de module print om o.a. pdf documenten te maken. Na het uitvoeren van de print pdf opdracht krijg ik de volgende foutmelding:
•Warning: getimagesize() [function.getimagesize]: URL file-access is disabled in the server configuration in theme_print_pdf_tcpdf_header() (regel 485 van /home/hervormd/public_html/sites/all/modules/print/print_pdf/print_pdf.pages.inc).
•Warning: getimagesize(http://hervormd-oud-vossemeer.nl/pkn_logo_nieuw.png) [function.getimagesize]: failed to open stream: no suitable wrapper could be found in theme_print_pdf_tcpdf_header() (regel 485 van /home/hervormd/public_html/sites/all/modules/print/print_pdf/print_pdf.pages.inc).
•Warning: curl_setopt() [function.curl-setopt]: CURLOPT_FOLLOWLOCATION cannot be activated when safe_mode is enabled or an open_basedir is set in TCPDF->Image() (regel 7400 van /home/hervormd/public_html/sites/all/modules/print/lib/tcpdf/tcpdf.php).

Hieronder staat de functie theme_print_pdf_tcpdf_header in het bestand print_pdf.pages.inc:
function theme_print_pdf_tcpdf_header($vars) {
$pdf = $vars['pdf'];
preg_match('!(.*?)!si', $vars['html'], $tpl_logo);
preg_match('!(.*?)!si', $vars['html'], $tpl_title);
preg_match('!(.*?)!si', $vars['html'], $tpl_site_name);

$ratio = 0;
$logo = '';
if (preg_match('!src\s*=\s*(?:\'(.*?)\'|"(.*?)"|([^\s]*))!i', $tpl_logo[1], $logo_url)) {
$logo = $logo_url[1];
$size = getimagesize($logo);
$ratio = $size ? ($size[0] / $size[1]) : 0;
}

// set header font
$pdf->setHeaderFont($vars['font']);
// set header margin
$pdf->setHeaderMargin(5);
// set header data
$pdf->setHeaderData($logo, 10 * $ratio, html_entity_decode($tpl_title[1], ENT_QUOTES, 'UTF-8'), html_entity_decode(strip_tags($tpl_site_name[1]), ENT_QUOTES, 'UTF-8'));

return $pdf;
}

Wat gaat er fout en moet ik aanpassen in de bovenstaande functie ?

Alvast bedankt voor het meedenken.