PHP 5.4 problems using &amp in http query

I'm having some problems when I perform an xml reading procedure from an external page.

When I run by shell php get.php the return is what I expect.

but when I run via browser the return is :

PHP Warning: simplexml_load_file(): I/O warning : failed to load external entity "http://------------/search.php?q=CITY&format=xml" in /var/www/html/get.php on line 5

how do I disable use of &amp when the query is via browser?

FILE get.php content:

ini_set('arg_separator.input', '&'); 
ini_set('arg_separator.output', '&'); 
$request_url = "--------/search.php?q=CITY&format=xml";
$xml = simplexml_load_file($request_url);
$json = json_encode($xml);
$array = json_decode($json, TRUE);