Im getting this error...

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /hsphere/local/home/mlongcos/cosdonline.org/conferences/register_05.php on line 155

Cant figure out why this isnt working... somebody please help!

The file is attached

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Suggest you echo out your sql statement to verify that it is being built correctly from the supplied variables. In this case it looks like you are using a variable for the table name, but there is no local decalaration of that variable.

when you use mysql_num_rows, you need to specify the pointer you are usign, eg:

$result1 = mysql_query($query1);
$result2 = mysql_query($query2);
echo "There are ".mysql_num_rows($result1)." rows in the first query\n";
echo "There are ".mysql_num_rows($result2)." rows in the second query\n";

//most of the time you use mysql_num_rows in a for loop, eg:
for ($i=0; $i<mysql_num_rows($result1); $i++) {
     $row = mysql_fetch_row($result1);
     echo $row[0]."-".$row[1]."\n";
}

//but if you don't care how many rows there are, you could just do the following:
while ($row = mysql_fetch_row($result2))
     echo $row[0]."-".$row[1]."\n";
}

the for loop and the while loop will do the exact same thing, except one uses result1 and the other result2

oah my bad, I just realized that you had the php file attached and you didn't make the mistake I assumed you did...

try putting some more checks in there to see where your errors are, anywhere you see __LINE__ it will print out the exact line the error occured in the PHP file. Very helpful if you do a lot of copying and pasting of code and don't feel like making unique error messages

$db=mysql_connect($db_loc, $db_usr, $db_pas) or die ("Unable to connect to the database. (". __LINE__.")");
mysql_select_db($db_db, $db)  or die ("Unable to connect to the selected database. (". __LINE__.")");

$echeck=mysql_query("SELECT * FROM $db_tab1 WHERE r_email LIKE '$email'",$db);

if ($echeck == 0) {
	      echo("<b>Error (".__LINE__.")" . mysql_errno($echeck) . ": " . mysql_error($echeck) . "</b>");
}

if (mysql_num_rows($echeck)) {	// E-Mail address already registered
	$message.=">> The E-Mail address you have provided, already exists in our database.\n<br>";
}
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