mysql_num_rows() error! plz help quick!

[techiefreak05]

[code]<?php
function userExists($a){
  global $conn;
  $q = "select username from users where username = '$a'";
  $result = mysql_query($q,$conn);
  return (mysql_num_rows($result) > 0);
}

if($_POST['sendMess']){
$to = $_POST['to'];
$from = $_SESSION['username'];
$message = $_POST['message'];
$subject = $_POST['subject'];
$date = date("D M j G:i:s T Y");

  if(userExists($_POST['to'])){
echo "<font color=red>Your Message has been sent!</font>";
mysql_query("INSERT INTO `messages` ( `from` , `to` , `message` , `date` , `status` , `subject`)
VALUES ('$from', '$to', '$message', '$date', 'no', '$subject');") or die("There was an error sending your message");
mysql_query("INSERT INTO `outbox` ( `from` , `to` , `message` , `date` , `status` , `subject`)
VALUES ('$from', '$to', '$message', '$date', 'no', '$subject');") or die(mysql_error());
}else{
echo "<font color=red>That Username does not exist! Your message has not been sent</font>";
}
}
?>
<form action="" method="post">
      <table align="center" border="0" cellspacing="0" cellpadding="3">
<tr><td bgcolor="#66CCCC"><font color=black>To:</font></td><td bgcolor="#6699CC"><input type="text" name="to" size="35"></td></tr>
<tr><td bgcolor="#66CCCC"><font color=black>Subject:</font></td><td bgcolor="#6699CC"><input type="text" name="subject" size="35"></td></tr>
<tr><td bgcolor="#66CCCC"><font color=black>Message:</font></td><td bgcolor="#6699CC"><textarea name="message" rows="10" cols="55"></textarea></td></tr>
<tr><td colspan="2" align="right"><input type="submit" name="sendMess" value="-Send Message-"></td></tr>
</table>
</form>[/code]

thats my form and php code to send a message, well my friends but when he tried it.. it says
[code]Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource in /home/www/flamelicker.com/newsite/login/sendMessage.php on line 15 [/code]

it wont be line 15, cuz there is no mysql_num_rows on that line and i took out the DB conenct stuff.. so why is it getting that error??

[Corona4456]

you never connect to the mysql server

[techiefreak05]

yes i did, if you read my post i said [code]it wont be line 15, cuz there is no mysql_num_rows on that line and [b]i took out the DB conenct stuff[/b].. so why is it getting that error??[/code]

i meant i took out the DB conenct info to post on here.. but its there in the actual file

[.josh]

are you sure you are actually connecting to the db? right db name, pw, etc..?

[Corona4456]

how do you know it's mysql_num_rows()? Could you please give us your error and not your friend's? That doesn't help us any.  The error is misguiding since it's your friend who got the error not you.

[techiefreak05]

ok, i have the EXACT same code as he does..and it works just fine! and yes, i get the same error as he does when i go to his page... so idk what could be wrong...

[techiefreak05]

oh duh, the error i first posted is a mysql_query error! haha well its both a query and num_rows error.. they both say the same thing