mysql_num_rows() expects parameter 1 to be resource

[el3reef]

Hello,

i'm using query like that

$result = mysql_query("SELECT * FROM workshop_months_records where month_date LIKE '$month_date' limit 1");
$result_num_row = mysql_num_rows($result);

and this error return to me

Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in ..../includes/class_postbit.php(289) : eval()'d code on line 103

Although the plugin was work perfectly on version 3

waiting for help

thanks