MySQL Errors

I am getting the following errors when I execute a php script. Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource Warning: mysql_fetch_row(): supplied argument is not a valid MySQL result resource Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource What do I need to make this work? I am new to PHP. I read something about mysql.class.php somewhere. Do I need that somewhere? Do I put an include in the main script? Where does mysql.class.php go directory-wise? I am sure I am not giving enough information and may not be explaining it good enough. My apologies. Again, I am new at this. I appreciate any help. Thank you in advance. Mike