Please try using this CVS snapshot:

  http://snaps.php.net/php5-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5-win32-latest.zip

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

The bug still exists in PHP 5.2.9!

Bug still there at PHP 5.2.13

OS -  redhat linux
Build Date - May 1 2010 23:54:46

curl_error($ch) returns 'Couldn't resolve host'
curl_errno($ch) returns 0

PHP 5.4.15 CURL 7.30.0 CentOS 6.4 64BIT

demo.php
<?php
$ch1 = curl_init();
curl_setopt($ch1, CURLOPT_URL, "http://localhost/sleep.php");
curl_setopt($ch1, CURLOPT_HEADER, 0);
curl_setopt($ch1, CURLOPT_TIMEOUT, 1);
$mh = curl_multi_init();
curl_multi_add_handle($mh,$ch1);

$active = null;
do {
	$mrc = curl_multi_exec($mh, $active);
} while ($mrc == CURLM_CALL_MULTI_PERFORM);

while ($active && $mrc == CURLM_OK) {
	if (curl_multi_select($mh) != -1) {
		do {
			$mrc = curl_multi_exec($mh, $active);
		} while ($mrc == CURLM_CALL_MULTI_PERFORM);
	}
}
echo curl_errno( $ch1); //0
echo '<br />';
echo curl_error( $ch1); //Operation timed out after 1004 milliseconds with 0 out 
of -1 bytes received
curl_multi_remove_handle($mh, $ch1);
curl_multi_close($mh);

sleep.php
<?php
sleep( 60);