Emailing blank PDFs

I don't know what your issue is exactly but the error I was getting was that the line

$attachment->filecontent = theme('webform2pdf_mail2pdf', $webform2pdf_send2pdf['nid'], $webform2pdf_send2pdf['sid']);

was not passing in proper values.

$webform2pdf_send2pdf['nid']
and
$webform2pdf_send2pdf['sid']

were always sending 1 and 1 respectively to the themeing function.

but the proper values were still in the

$message['params']['submission']

I don't know if that is helpful to you.

Are you still in this function?
function webform2pdf_mail_alter(&$message)
Sorry I haven't looked at the dev version.

My code looks like this for the area where I was having issues

 if ( $attach_pdf ) {
        $node = node_load($webform2pdf_send2pdf['nid']);
        $filename = theme('webform2pdf_filename', array('node' => $node, 'submission' => $webform2pdf_send2pdf['sid']));
        unset($node);
        $nid = $message['params']['submission']->nid;
        $sid = $message['params']['submission']->sid;
        if (webform_email_html_capable()) {
          if (module_exists('mimemail')) {
            $attachment = new stdClass;
            $attachment->filecontent = theme('webform2pdf_mail2pdf', array('nid'=>$nid,'sid'=>$sid));
            $attachment->filename = $filename;
            $attachment->filemime = 'application/pdf';
            $message['params']['attachments'][] = $attachment;
          }
        }