Actually the my fix for this problem is on the PHP side, 
not in the PHP-code it self:


function jk_ip2long ($ip) {
    
preg_match("#^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$#", 
$ip, $a);

    $long = 
      $a[1] << 24 | 
      $a[2] << 16 |
      $a[3] <<  8 |
      $a[4] <<  0;
    
    ## handling negative urls
    if($long < 0) $long += pow(2,32); 
    
    return $long;
}

## long2ip

function jk_long2ip ($long) {
    ## handle long value which should be signed in PHP but 
are unsigned
    
    if ($long > 0x7fffffff) {
        ## although this code seems to be useless, it does 
what we want
        $l = ($long - 0x7fffffff) - 1;
        $long = -(0x7fffffff - $l) - 1;
    }
    
    
    $ip3 = sprintf("%d.%d.%d.%d",
                   $long >> 24 & 0xff,
                   $long >> 16 & 0xff,
                   $long >>  8 & 0xff,
                   $long >>  0 & 0xff
                   );
    return $ip3;
}

You can see a working example at

http://jan.kneschke.de/projects/phpbugs/ip2long.php