Not sure what I'm doing wrong with this query

[Derek Rouleau]

This is the code I'm having a problem with:
//$sql = "SELECT SQL_CALC_FOUND_ROWS * FROM " . TBL_MEMBERS . " ORDER BY $order LIMIT :startRow, :numRows";
$sql = "SELECT SQL_CALC_FOUND_ROWS * FROM " . TBL_MEMBERS . " ORDER BY $order LIMIT $startRow, $numRows";

try {
$st = $conn->prepare( $sql );
$st->bindValue( ":startRow", $startRow, PDO::PARAM_INT );
$st->bindValue( ":numRows", $numRows, PDO::PARAM_INT );
$st->execute();
$members = array();
foreach ( $st->fetchAll() as $row ) {
$members[] = new Member( $row );
}

Ok, if I run the non-commented out version of the SQL it works fine and I get the result I expect, however if I run the commented out version I get the following error:

Query failed 1: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''5'' at line 1

I printed this out at the start of the function to check the values:

startRow = 0 and numRows = 5

It looks like something around the last value as that is where the "5" is.

I'm sure it's something stupid as I only spend about 5 - 10 hours a month doing PHP, so thank you in advance!

oh yeah:

mysql> select version();
+-------------------------+
| version() |
+-------------------------+
| 5.5.24-0ubuntu0.12.04.1 |
+-------------------------+
1 row in set (0.00 sec)