สอบถามปัญหา ติด error ครับ ++++$num=mysql_num_rows($result);

<?php
$host="localhost";
$user="root";
$passwd="666666";
$dbname="register";
mysql_connect($host,$user,$passwd) or die("?????? Host ????????????");
mysql_select_db($dbname) or die("?????????????????????");
$sql="insert into 'userinfo' ('logname','pw','name','address','age','gender','ads','hobby1','hobby2','hobby3','hobby4','hobby5')
	values('$logname','$psswd','$name','$address','$age','$gender','$Uknow','$hobby1','$hobby2','$hobby3','$hobby4','$hobby5')";
mysql_query("set NAMES tis620");
$sqlquery=mysql_db_query($dbname,$sql);
$checkadd="select * from 'userinfo' where logname='$logname'";
$result=mysql_db_query($dbname,$checkadd);
$num=mysql_num_rows($result); 
	if($num==1)
	{
		print"<??????????????????????????????????????????????>";
	}
mysql_close();
?>