failed to load external entity “”

[cegeclofs]

Basically this is a search bar and I take the searched for term and put it in the api call url, however i'm getting \[quote\] Warning: simplexml_load_file() [function.simplexml-load-file]: I/O warning : failed to load external entity ""\[/quote\]any ideas?code:\[code\]if (!empty($_POST['searchbird'])){ $searchbird=rawurlencode($_POST['searchbird']); $searchCode = "http://ebird.org/ws1.1/data/obs/region_spp/recent?rtype=subnational2&r=US-AZ-013&sci=$searchbird"; $url_headers = @get_headers($searchCode); if($url_headers[0] == 'HTTP/1.1 200 OK') { $xml = simplexml_load_file($url); print_r($xml); } else { // Error echo $searchCode; print_r($url_headers); exit("failed to load XML"); }} else { $searchbird = ''; $form = "<form method='post'> <strong>Enter the name of a Bird</strong> <input type='text' name='searchbird' value='http://stackoverflow.com/questions/15755274/$searchbird' /> <input type='submit' name='submit' value='http://stackoverflow.com/questions/15755274/submit' /> </form>"; echo $form;}\[/code\]