php - Syntax error or access violation using PDO

I'm migrating my local files online and having PHP issues with my db script. Works fine locally (running PHP 5.3.8) but gives me the following errors on my server (PHP 5.3.10)

Without $DBH->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );

Fatal error: Call to a member function setFetchMode() on a non-object in /.../...php on line 108

With $DBH->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );

SQLSTATE[42000]: Syntax error or access violation: 1142 SELECT command denied to user '...'@'205.186.180.26' for table 'invited'

Here is my code:

class guest {
    public $id;
    public $guest_name;
    public $url_phrase;
}

$guest = new guest;


if (isset($_GET['p'])) {
    $url_phrase = urldecode($_GET['p']); 
} else if (isset($_POST['p'])) {
    $url_phrase = urldecode($_POST['p']); 
}

if (isset($url_phrase)) {

    try {


    $DBH = new PDO("mysql:host=myhost.com;dbname=mydbname", "myusername", "mypassword");
    $DBH->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );

    $url_phrase = $DBH->quote($url_phrase);
    $sql = "SELECT id, guest_name, url_phrase FROM mydbname.invited WHERE url_phrase = $url_phrase";

    $stmt = $DBH->query($sql);
    $stmt->setFetchMode(PDO::FETCH_INTO, new guest);

    $guestNumber = $stmt->rowCount();


    if($guestNumber > 0) {
        etc...  
    }
    if($guestType == "solo") {
        foreach($stmt as $guest) {
            $name = $guest->guest_name;
            etc...  
        }
    }

} else {
    other stuff.. etc..
    $DBH = null;
} catch (PDOException $e) {
    echo $e->getMessage();
}
}

I've gotten simple select statements to work fine as this user (I don't think its permission-related), my problem seems to be with my implementation of PDO. How can I get rid of this error? Am I preparing/executing the statement in a weird way that's messing this up? Thanks for any help