Pagination with PDO prepare statement - pdo

Question

I am using David Carr's pagination class successfully for a whole-table call (i.e. where I'm calling all the rows in the table without filtering). After including my config and the class, I accomplish it this way:
$pages = new Paginator('3','p');
$stmt = $dbh->query('SELECT count(id) FROM sermons');
$row = $stmt->fetch(PDO::FETCH_NUM);
$total = $row[0];
//pass number of records to
$pages->set_total($total);
$results = $dbh->query('SELECT * FROM sermons ORDER BY date_preached DESC '.$pages->get_limit()); ?>
<div class="paging"><p><?php echo $total; ?> sermons found</p> <?php echo $pages->page_links();?></div>
<?php
foreach($results as $row)
Etc.
That works great, but now I'm trying to implement it for the result of user filtering via forms, and because I can't use an unnamed placeholder in the query, I'm trying to do it with a prepare (which I'm guessing is more secure anyway):
$pages = new Paginator('2','p');
$series = isset($_POST['series']) ? $_POST['series'] : false;
try {
$stmt = $dbh->prepare("SELECT count(id) FROM sermons WHERE series = ?");
$stmt->execute(array($series));
$row = $stmt->fetch(PDO::FETCH_NUM);
$total = $row[0];
//pass number of records to
$pages->set_total($total);
$results = $dbh->prepare("SELECT * FROM sermons WHERE series = ? ".$pages->get_limit());
$results->bindParam(1, $series, PDO::PARAM_STR);
$results->execute(array($series));
// the call
echo $total; ?> sermons found</p> <?php echo $pages->page_links();
When I first get to the results page from the form, it looks like everything is working properly. The call correctly identifies the number of sermons found for the search result, and displays the first two (or however many I set in the $pages statement). But when I click to another page result, no sermons display, the count is gone, and my !isset(found_rows) echo returns a zero as well.
I was originally thinking the issue was that at first I was trying to do this without binding. That is questionable, since without the pagination I can display the page without binding. In any case, I've been trying that with both bindValue and bindParam, but with no luck.
Am I mishandling something in the prepare statement? Or what?
Note: I have the results page displaying fine without the pagination with this:
$series = isset($_POST['series']) ? $_POST['series'] : false;
try {
$results = $dbh->prepare("SELECT * FROM sermons WHERE series = ?");
$results->execute(array($series));
// Etc.