PDO - Fatal error: Call to a member function fetch() on a non-object [duplicate]

Answer 1

Where is your Execute statement being called? Is this also inside your ->query ? If not think of using the following for also a better query build up.:

getMessage();
            }
            $statement = "SELECT user, captcha FROM xf_captcha WHERE user=:username";
            //If you have query as a method(Which I don't think so but if you can change "prepare" to your "query"
            $sth = $dbh->prepare($statement);
            $sth->execute(array(":username" => $username));
            $row = $sth->fetch(PDO::FETCH_ASSOC);
    ?>

In the execute parentheses you can use an array to fill the parameter :username for the variable $username

I think looking into PDO Class examples might also be good for a better understanding of PDO and methods(You can also refer to the PHP PDO Manual)