What error does it give? See http://www.php.net/curl_error

The error returned by cURL is:
22 The requested URL returned error: 404

I created this function which solves the problem:

function urlencode_url($url) {
   if (!($ei=strpos($url,"?"))) $ei=strlen($url);
   $newurl=str_replace(array("%3A","%2F"),array(":","/"),urlencode(urldecode(substr($url,0,$ei)))).substr($url,$ei);
   return $newurl;
}

By passing the URL through this function, the offending character is converted to its urlencoded equivalent (%##). With these codes instead of the bad character, cURL reads the URL with no problem.

Nonetheless, I reported this issue because Internet Explorer does not require the urlencoded codes. It loads the original URL with no problem, using the original bad character in the URL. Therefore, the cURL behavior is more strict in its requirement of the URL being urlencoded than Internet Explorer is.

Perhaps cURL could automatically urlencode the URL, or perhaps a function should be made for this purpose like the one I have shown above.

Well, browsers do a lot of thing automatically you need to do yourself 
when you do it yourself. This is obviously not any bug. (tested with 
curl on command line with same result..)