vari errori di semplici codici php che non mi vengono

[LorisMi]

<?php

class CookieCounter extends SimpleCounter
{
    
    public function __construct(DataProvider $provider)
    {
        parent::__construct($provider);
    }
    
    public function isValid()
    {
        if(!isset($_COOKIE['counter_cookie']))
        {
            setcookie('counter_cookie', '1', time() + 3600);
           
            return true;
        }
       
        return false;
    }
}

?> 
<?php

require_once 'lib/counter.php';
require_once 'lib/cookiecounter.php';

$counter = new CookieCounter(new FileDataProvider);

echo "Questa pagina &egrave; stata visitata ".$counter->visits." volte";

?>

errore che mi da:

Fatal error: Class 'SimpleCounter' not found in C:\www\cookiecounter.php on line 3

<?php

require_once 'lib/counter.php';
require_once 'lib/cookiecounter.php';

$counter = new CookieCounter(new FileDataProvider);

echo "Questa pagina &egrave; stata visitata ".$counter->visits." volte";

?>

Errore:

Warning: require_once(lib/counter.php) [function.require-once]: failed to open stream: No such file or directory in C:\www\index.php on line 5

Fatal error: require_once() [function.require]: Failed opening required 'lib/counter.php' (include_path='.;c:\php\includes;c:\php\PEAR') in C:\www\index.php on line 5

<?php 
mail("g.farina@html.it", "mesaggio di prova", "Questo è un messaggio di prova testuale", "From: [email]test@html.it[/email]"); 
?>

errore:

Warning: mail() [function.mail]: Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set() in C:\www\mail.php on line 2

Ho postato questi errori per capirci un pò di più... grz 1000

[LorisMi]

Come risolverli?

[nICO80]

Fatal error: Class 'SimpleCounter' not found in C:\www\cookiecounter.php on line 3

Warning: require_once(lib/counter.php) [function.require-once]: failed to open stream: No such file or directory in C:\www\index.php on line 5

Fatal error: require_once() [function.require]: Failed opening required 'lib/counter.php' (include_path='.;c:\php\includes;c:\php\PEAR') in C:\www\index.php on line 5

Immagino che ti manchi il file lib/counter.php che definisce la classe SimpleCounter...

Warning: mail() [function.mail]: Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port" setting in php.ini or use ini_set() in C:\www\mail.php on line 2

Hai un mailserver installato?