database insertion signup failed - php

Question

<?php require 'header.inc.php';
require 'connect.inc.php'; ?>
<?php
$reg = #$_POST['reg'];
$fn = "";
$ln = "";
$un = "";
$em = "";
$pswd = "";
$d = "";
$u_check = "";
$fn = strip_tags(#$_POST['fname']);
$ln = strip_tags(#$_POST['lname']);
$un = strip_tags(#$_POST['uname']);
$em = strip_tags(#$_POST['email']);
$pswd = strip_tags(#$_POST[ 'pass']);
$d = date('Y-m-d');
if($reg){
if($fn&&$ln&&$un&&$em&&$pswd){
$u_check = mysql_query("SELECT uname FROM users WHERE uname='$un'");
$check = mysql_num_rows($u_check);
if ($check == 0) {
if (strlen($un)<4||strlen($fn)<4||strlen($ln)<4) {
if (strlen($un)>20||strlen($fn)>20||strlen($ln)>20) {
echo "<div id=\"errormsg\"> <p>username/first name/last should not be over 20 characters</p> </div>";
}else {
$pswd = md5($pswd);
$query = mysql_query("INSERT INTO users VALUES ('','$un','$fn','$ln','$em','pass')");
die("welcome to vydoo");
}
}else {
echo "<div id=\"errormsg\"> <p>username/first name/last should not be under 4 characters</p> </div>";
}
}else {
echo "<div id=\"errormsg\"> <p>Username is allready taken</p> </div>";
}
}else {
echo "<div id=\"errormsg\"> <p>Please fill in all fields</p> </div>";
}
}
?>
<div class="content">
<div class="infos">
<p class="w">Sign Up and discover the great community</p>
<p class="s">Sign up in few steps , its free and unlimited</p>
</div>
<form class="form" method="POST">
<input class="Firstname" type="text" name="fname" placeholder="Fisrt name">
<input class="Lastname" type="text" name="lname" placeholder="Last name">
<input class="username" type="text" name="uname" placeholder="Usename">
<input class="email" type="email" name="email" placeholder="Email">
<input class="pass" type="password" name="pass" placeholder="Password">
<input class="submit" type="submit" name="reg" valueenter code here="Sign In">
</form>
i does not send information to database ! where is the problem please , i corrected every signle mistake in there and i cant find where is the problem , i have allready asked this question but with a different code , now i dont find my wrong code