information not inserting into database

[Collegeboox]

information not posting into the database the code below is the check code/insert code. Please if anyone knows why let me know.

 

[color=red]<?php
//msut be logged in page
session_start();

if  ($_SESSION['username'])
{
echo"";
}
else
die("You must log in first!");

//form information
$submit = $_POST['submit'];
$row4 = $_SESSION['username'];

// form data
$link = strip_tags($_POST['link']);
$message = strip_tags($_POST['message']);
$title = strip_tags($_POST['title']);
$author = strip_tags($_POST['author']);
$date = date('Y-m-d');


$connect = mysql_connect("db","username","password") or die("Not connected");
mysql_select_db("username") or die("could not log in");
$querycheck = "SELECT * FROM boox WHERE username='$row4'";
$result = mysql_query($querycheck);
while($rowz = mysql_fetch_array($result))

$linkcheck = $rowz['link'];


if ($submit)
{
if($link&$title&$author)
{
	// check username and subject lentgh
	if ($linkcheck == $link)
	{
		die ("This link has already been posted.");
	}
	else

		{
			//open database
			$connect = mysql_connect("db","username","password") or die("Not connected");
			mysql_select_db("username") or die("could not log in");
			$queryreg = mysql_query("INSERT INTO boox Values ('','$row4','$link','$title','$author','$message','$date')");
			echo "You have just officialy posted on the Catalina Beat Mixers. ";

		}

}

}
		   
else
{
	die ("You forgot to put something in the link/title/author box.");
    }


?>[/color]
[code]

[jcbones]

De-bugging added, please copy/paste the error that is printed to the screen.

<?php
//msut be logged in page
session_start();
//display all errors.
error_reporting(-1);
ini_set('display_errors',1);

if  ($_SESSION['username'])
{
echo"";
}
else
die("You must log in first!");

//form information
$submit = $_POST['submit'];
$row4 = $_SESSION['username'];

// form data
$link = strip_tags($_POST['link']);
$message = strip_tags($_POST['message']);
$title = strip_tags($_POST['title']);
$author = strip_tags($_POST['author']);
$date = date('Y-m-d');


$connect = mysql_connect("db","username","password") or die("Not connected");
mysql_select_db("username") or die("could not log in");
$querycheck = "SELECT * FROM boox WHERE username='$row4'";
$result = mysql_query($querycheck) or trigger_error(mysql_error()); //error trigger added.
while($rowz = mysql_fetch_array($result))

$linkcheck = $rowz['link'];


if ($submit)
{
if($link&$title&$author)
{
	// check username and subject lentgh
	if ($linkcheck == $link)
	{
		die ("This link has already been posted.");
	}
	else

		{
			//database is already open
			$queryreg = mysql_query("INSERT INTO boox Values ('','$row4','$link','$title','$author','$message','$date')") or trigger_error(mysql_error()); //added a error trigger on query failure.
			echo "You have just officialy posted on the Catalina Beat Mixers. ";

		}

}

}
		   
else
{
	die ("You forgot to put something in the link/title/author box.");
    }


?>
[code]