problem with php mail. Some functions don´t work

<form method='POST' action='' enctype='multipart/form-data'>
<table id='row'>
	<tr>
		<td><select id="to" name='to[]'>
			<option value='To:'>to:</option>
			<option value='Cc:'>CC:</option>
			<option value='Bcc:'>BCC:</option>
			<option value='Reply-To:'>Reply-To:</option>
			<select></td><td><input type='text' id='adr' name='mail[]'><input type='button' onclick='newAdres ()' value='+'></td>
	</tr>

$art = array();
	$art = $_POST['to'];
	$bet=$_POST['betr'];
	$text=$_POST['text'];
	$to = array();
	$to=$_POST['mail'];
	$header = array();
	$header[] = "From: me < me@nnn.com >";
	$header[] = "MIME-Version: 1.0";
	$header[] = "Content-type: text/plain; charset=iso-8859-1";
	$header[] = "X-Mailer: PHP/".phpversion();
	
	$i=0;
	while (isset($art[$i])){ //Header (Bcc, Cc,... )
		$j=$i+4;
		$header[$j] = "$art[$i] $to[$i]";
		$i++;
	}
mail(null,$bet, $text, implode("\r\n", $header));