Array to string conversion error when executing PDO statement

Question

There are many questions on stackoverflow regarding an error printing "Array to string conversion" but none seem to help me.

I'm trying to execute a sql select statement with php. Here is a bit of what im dealing with:

public static function getNumCGS(){
    require 'includes/vars.php';
    $paramArray = array(":table" => "campground_data");
    $query = Utilities::dbSelect("SELECT count(*) FROM :table","campgrounddata", $paramArray);
    $r = $query->fetch();
    return $r["count(*)"];
}

In Utilities.php:

public static function dbSelect($selectStmt, $dbName, $params){
    require_once "config/config.php";
    $dbh = Config::connect($dbName);
    $query = $dbh->prepare($selectStmt);
    $query->setFetchMode(PDO::FETCH_ASSOC);
    $query->execute($params) or die("DB Error: " . $query->errorInfo());
    return $query;
}

In Config.php:

public static function connect($dbname){
    $dbserver = "localhost";
    $dbuser = "sys";//just a local server
    $dbpass = "test1";//just a local server
    try {
        $dbh = new PDO("mysql:host=$dbserver;dbname=$dbname", $dbuser, $dbpass, NULL);
        return $dbh;
    }
    catch (PDOException $e) {
        printf("ERROR: %s", $e->getMessage());
        exit();
    }
}

If I call getNumCGS() It tells me that I have an Array to string conversion problem at the line that executes the query in the dbSelect function.

I've been following an example from a text book, not sure what the deal is. The example I'm seeing passes in an array into the execute call.