code ที่มัน Error ใครรู้ช่วยหน่อยครับ Code Warning: mysql_free_result(): supplied argument is not a valid MySQL result resource in

<?php
if (!isset($_GET["y"])){ // แก้ตรงนี้
	$year = date('Y');
}else{
	$year = $_GET["y"]; // แก้ตรงนี้
}

$link = mysql_connect('localhost','root','191130');
if(!$link){
	die('Could not connected'.mysql_error());
}
//echo 'Connected successfully';

mysql_select_db("radius");

/*
$strSql="SECECT Distinct GroupName FROM usergroup u";
$result = mysql_query($strSql);
echo $year;
echo "<table border = 1>";
while($row = mysql_fetch_array($result,MYSQL_ASSOC)){
echo"<tr><td>".$row["GroupName"]."<td>";
for($month=1;$month<=12;$month++) { 
$strSql2= " SELECT GroupName,Year(AcctStartTime)As year,Month(AcctStartTime)As month ,Count(*)As Count FROM radius.radacct, radius.usergroup u where radius.UserName= u.UserName Group by GroupName,Year(AcctStartTime),Month(AcctStarTime) Having year = ".$year."and month = ".Month."and GroupName = ".$row["GroupName"].""; 
$result2 = mysql_query($strSql2); 
$num_rows = mysql_num_rows($result2);
if($num_row == 0) {
$row2["Count"]=0;
}
else{
$row2=mysql_fetch_array($result2);
}
echo "<td>".$row2["Count"]."</td>";
}
echo "</tr>";
}
echo "</table>";
*/ 

$data =array(); // แล้วนี้array อะไร

$strSql="SELECT GroupName,Year(AcctStartTime)As year,Month(AcctStartTime)As month,Count(*)As count From radius.radacct,radius.Usergroup u where radacct.UserName = u.UserName Group by GroupName,Year(AcctStartTime),Month(AcctStarTime) Having year = ".$year."";

$result = mysql_query($strSql);

echo"<table border = 1>";
while($row = mysql_fetch_array($result,MYSQL_ASSOC)){
echo "<tr>";
echo "<td>".$row['GroupName']."</td>";
echo "<td>".$row['year']."</td>";  
echo "<td>".$row['month']."</td>"; 
echo "<td>".$row['count']."</td>"; 
echo "</tr>";
$data[$row["GroupName"]][$row["year"]][$row["month"]]=$row["count"];// ลองดูตรงนี้หน่อยนะครับงงมากเลย
}
echo "</table>";

echo $year;
echo "<table border = 1>";
echo "<tr>";
echo "<th>UserName</th>";
echo "<th>Jan</th>";
echo "<th>Feb</th>";
echo "<th>Mar</th>";
echo "<th>Apr</th>";
echo "<th>May</th>";
echo "<th>Jun</th>";
echo "<th>Jul</th>";
echo "<th>Aug</th>";
echo "<th>Sep</th>";
echo "<th>Oct</th>";
echo "<th>Nov</th>";
echo "<th>Dec</th>";
echo "</tr>";
foreach($data as $GroupName=>$val){
echo "<tr>";
echo "<td>$GroupName</td>";
foreach($val as $year=>$val2){
//print "Key $year,Value $val2\n";
//echo "<td>$year</td>";
//foreach($val2 as $month=>$val3){
for($month=1;$month<=12;$month++){
//echo "<td>$month =val3</td>";
//echo "<td>$val3</td>";
if(isset($data[$GroupName][$year][$month])){
echo "<td>".$data[$GruopName][$year][$month]."</td>";
}
else{
echo "<td>0</td>";
}
}
}
echo "</tr>";
}
echo "</table>";

mysql_free_result($result);
mysql_close($link); // แก้ตรงนี้
?>