getimagesize() problem with WP-symposium

I have set up a forum on a small website https://wightwestiewalkers.org.uk the site is a members only site and there is an odd issue occuring on the forum pages which appears above each post:-

Warning: getimagesize() [function.getimagesize]: URL file-access is disabled in the server configuration in /homepages/38/d168328470/htdocs/.Westies/wp-content/plugins/wp-symposium/functions.php on line 559

Warning: getimagesize(https://www.wightwestiewalkers.org.uk/wp-content/wps-content/forum/9/1_229903_4721091464283_554493021_n.jpg) [function.getimagesize]: failed to open stream: no suitable wrapper could be found in /homepages/38/d168328470/htdocs/.Westies/wp-content/plugins/wp-symposium/functions.php on line 559

I have copied the php mark-up from the wp-symposium functions.php but can’t see where the issue is (I am a complete PHP virgin)

if (get_option(WPS_OPTIONS_PREFIX.'_forum_thumbs') == 'on') {
											//list($width, $height, $type, $attr) = getimagesize($url);
											list($width, $height, $type, $attr) = getimagesize(parse_url(get_bloginfo('url'),PHP_URL_SCHEME)."://".parse_url(get_bloginfo('url'),PHP_URL_HOST).$url);
											$max_width = get_option(WPS_OPTIONS_PREFIX.'_forum_thumbs_size');
											if ($width > $max_width) {
												$height = $height / ($width / $max_width);
												$width = $max_width;
											}
											$html .= '<img src="'.$url.'" rev="'.$cnt_cont.'" rel="symposium_gallery_photos_'.$post->tid.'" class="wps_gallery_album" style="width:'.$width.'px; height:'.$height.'px" />';
											$cnt_cont++;

										} else {
											$html .= $file;
										}
										$html .= '</a> ';
									} else {

Can anyone point me in the right direction to sort this issue out.