Pl. could you list your tried sample lines, I executed with the following and still getting the permission denied error (I also tried uncommenting sasl.php, tls=1, authentication_mechanism=""....same error). 
require_once pop3.php");
// require{"sasl.php");
$pop3=new pop3_class;
$pop3->hostname="pop.bizmail.yahoo.com";                 
$pop3->port=995; 
$pop3->tls=0;
$user="
[email protected]"; 
$password="pop3class"; 
$pop3->realm=""; 
$pop3->workstation=""; 
$apop=0;
$pop3->authentication_mechanism="USER";
$pop3->debug=1; 
$pop3->html_debug=1;
$pop3->join_continuation_header_lines=1;
	if(($error=$pop3->Open())=="")
	{
		echo "<PRE>Connected to the POP3 server "".$pop3->hostname."".</PRE>\n";
		$error = $pop3->Login($user,$password, $apop);
		echo "done";
	} else print ($error);