Help with mysql error

here is my code:

<?php

$desire_schedule = '0';

if(isset($_POST['update_users'])){

echo '<br /><div align="center">';

if(isset($_POST['schedman'])){
$checked = $_POST['schedman'];
if($checked == 'Yes'){
$desire_schedule = '1';
}
else {
$desire_schedule = '0';
}

$stop = "false";
echo '<br /><div align="center">';

$names1 = trim($_POST['selected']);
$admin2_query = mysql_query("SELECT * FROM admins WHERE name = '$names1'");
$admin2_data = mysql_num_rows($admin2_query);
$admin_query = mysql_query("SELECT * FROM accounts WHERE name = '$names1'");
$admin_data = mysql_fetch_array($admin_query);
$usname = $admin_data['name'];
$email = $admin_data['email'];
$password = $admin_data['password'];
$zpassword = sha1($password);
$mpassword = md5($zpassword);

if($admin2_data != '0'){
echo '<font color="red">' . $usname . ' is already a schedule manager, please log into the schedule manager screen to erase them from allowable schedule managers';
$stop = "true";
}
else if($stop == "false"){
if($desire_schedule == '1'){
mysql_query("INSERT INTO `admins` (`username`, `password`, `email`) VALUES ('$usname', '$mpassword', '$email')");
echo '<font color="green">' . $usname . ' is now a schedule manager.';
$stop = "true";
}
} else if($stop == "false"){

if($desire_schedule == '0'){
$stop = "true";
}
}
}
echo '</font></div>';
}

?>


the connection to mysql is working just fine, when I put it on my site and attempt to use it, it outputs:


Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in update_users.php on line 77


I tried many google searches, and have been battling this for over 12 hours (I'm not very good at PHP or mysql i guess XD)

any input is greatly appreciated. thank you =)

Could you post the contents of line 77 in the indicated script please. I quickly reviewed your script and couldn't find any errors with the mysql_num_rows argument, so I was curious, maybe you have been looking in the wrong place?

Sounds like the query might be failing.

Try modifying the query that you are trying to get the number of rows on like so:
$admin2_query = mysql_query("SELECT * FROM admins WHERE name = '$names1'") or die(mysql_error());

That will print out the mysql error message if the query fails.

thanks to "oracleguy" I was able to figure it out, thank you =)

If you ever get an error with mysql you should use mysql_error() to work out what is wrong. It gives you a pretty good idea immediately
Also, you should use
$query = "SELECT ... $variable ...";
mysql_query($query);
This means that if your query isn't working as expected you can just use echo $query between those two lines and it will output what query is being run (when the variables have been inserted into the query)