ขอสอบถามเรืองการสมัครสมาชิกลง database แล้วไม่สามารถนำมาใช้งานได้ครับ

<? session_start(); ?>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<? 

require_once('Connections/db_connect.php'); 
$MEM_USER = $HTTP_POST_VARS['mem_user'];
$MEM_PASS = $HTTP_POST_VARS['mem_pass'];
$_SESSION['mem_user']= $MEM_USER;
$_SESSION['mem_pass']= $MEM_PASS ;
//print  $_SESSION['MEM_USER'];
//print  "<br>".$_SESSION['MEM_PASS'];
$sql = "SELECT mem_pass FROM  mem_ber WHERE mem_user='$MEM_USER' AND mem_pass='$MEM_PASS'";
//$sql = "SELECT * FROM  MEMBER WHERE MEM_USER='$MEM_USER' AND MEM_PASS='$MEM_PASS'";
//print  $sql;

$rs = mysql_query($sql);
$nrow = mysql_num_rows($rs);
$row=mysql_fetch_array($rs);
//if($nrow >=1){
if($nrow !=0){

//			$sql1=" SELECT  MEM_SCORE1 FROM MEMBER  WHERE  MEM_USER = '$MEM_USER' AND MEM_PASS = '$MEM_PASS' ";
//			//print $sql1;
//			$rs1 = mysql_query($sql1);
//			$nrow1 = mysql_num_rows($rs1);
//			$row1=mysql_fetch_array($rs1);
//			if($row1==0) {
//				print " <meta http-equiv=\"refresh\" content=\"0; URL=chap_1.php?ck=0\"> ";

//			}else {
				//print " <meta http-equiv=\"refresh\" content=\"0; URL=chap_1.php?ck=0\"> ";
						//$sql2=" SELECT  MEM_PRETEST_VALUE, MEM_SCORE1, MEM_SCORE2, MEM_SCORE3, MEM_SCORE_POST  FROM  MEMBER  WHERE MEM_USER ='$MEM_USER' and MEM_PASS='$MEM_PASS' ";
						$sql2=" SELECT  *  FROM  member  WHERE mem_user ='$MEM_USER' and mem_pass='$MEM_PASS' ";
						//print $sql2;
						$rs2 = mysql_query($sql2);
						$nrow2 = mysql_num_rows($rs2);
						$row2=mysql_fetch_array($rs2);
									
						$score1=$row2['mem_pretest_value'];
				        $score2=$row2['mem_score1'];
						$score3=$row2['mem_score2'];
						$score4=$row2['mem_score3'];
						$score5=$row2['mem_score_post'];
						//echo "1:".$score1."  2:".$score2." 3:".$score3." 4:".$score4." 5:".$score5;
					  if(($score>0) || ($score1==0)) {
										   //print " <meta http-equiv=\"refresh\" content=\"0; URL=chap_1.php\"> ";
										   print " <meta http-equiv=\"refresh\" content=\"0; URL=chap_1.php?cK=0\"> ";
					  }else if($score2<10) {
										  // print " <meta http-equiv=\"refresh\" content=\"0; URL=test1.php\"> ";
										  print " <meta http-equiv=\"refresh\" content=\"0; URL=chap1.php\"> ";
					  }else if($score3<10) {
											//print " <meta http-equiv=\"refresh\" content=\"0; URL=test2.php\"> ";
											print " <meta http-equiv=\"refresh\" content=\"0; URL=chap2.php\"> ";
						}else if($score4<10) {
											//print " <meta http-equiv=\"refresh\" content=\"0; URL=test3.php\"> ";
											print " <meta http-equiv=\"refresh\" content=\"0; URL=chap3.php\"> ";
						}else if($score5<15) {
											//print " <meta http-equiv=\"refresh\" content=\"0; URL=test4.php\"> ";
											print " <meta http-equiv=\"refresh\" content=\"0; URL=test4.php\"> ";
						}else if (($score1>0)&&($score2>=10)&&($score3>=10)&&($score4>=10)&&($score5>=15)){
									print " <meta http-equiv=\"refresh\" content=\"0; URL=chap_1.php?cK=1\"> ";
						}													
//					}
}else {
	print "<script>";
	print "alert('username หรือ password ไม่ถูกต้องค่ะ');";
	print "location.href='index.php';";
	print "</script>";
}
?>