PHP mysqli connection not working in separate php file

I have a blog that I am building and expanding to gain experience in php. I decided to move from mysql to the newer mysqli. I also created separate files that define variables and connect to the database. I have appConfig.php that defines all my variables and functions:

<?php
    define("DEBUG_MODE", true);
    define("SITE_ROOT", "http://blog.zacharysaathoff.com/");
    define("DATABASE_HOST", "127.0.0.1");
    define("DATABASE_USERNAME", "**********");
    define("DATABASE_PASSWORD", "**********");
    define("DATABASE_NAME", "**********");
    define("HOST_WWW_ROOT", "/home1/ohairclu/public_html/zsaathoffblog/");
    function js_redirect($url, $seconds=0) {  
        echo "<script language=\"JavaScript\">\n";  
        echo "<!-- hide from old browser\n\n";       
        echo "function redirect() {\n";  
        echo "window.location = \"" . $url . "\";\n";  
        echo "}\n\n";  
        echo "timer = setTimeout('redirect()', '" . ($seconds*1000) . "');\n\n";  
        echo "-->\n";  
        echo "</script>\n";  
        return true;  
    }  
    function handle_error($user_error_message, $system_error_message) {
        js_redirect('http://blog.zacharysaathoff.com/error.php?error_message='.$user_error_message.'&system_error_message='.$system_error_message, 0);
        exit();
    }
    function debug_print($message) {
        if (DEBUG_MODE) {
            echo $message;
        }
    }
    echo "configured";
?>

I also have databaseConnection.php which should connect to the database for me:

<?php
    require_once 'appConfig.php';
    global $mysqli;
    $mysqli = new mysqli(DATABASE_HOST, DATABASE_USERNAME, DATABASE_PASSWORD, DATABASE_NAME);
    if ($mysqli->connect_errno) {
        handle_error("There was a problem connecting to the database that holds the information we need to get you connected.", "Failed to connect to MySQL: (".$mysqli->connect_errno.") ".$mysqli->connect_error);
    }
    return $mysqli;
?>

I know global variables are not desirable. It was just something I tried. Same thing with the return. I know it probably doesn't belong there. The file I require these files in is homePageLinks.php:

<?php
    require_once 'appConfig.php';
    require_once 'databaseConnection.php';
    $mysqli = new mysqli(DATABASE_HOST, DATABASE_USERNAME, DATABASE_PASSWORD, DATABASE_NAME);
    if ($mysqli->connect_errno) {
        handle_error("There was a problem connecting to the database that holds the information we need to get you connected.", "Failed to connect to MySQL: (".$mysqli->connect_errno.") ".$mysqli->connect_error);
    }
    $stmt = $mysqli->prepare("
        SELECT `date`, `title`, `path`, `image_path`
        FROM `ohairclu_blog_comments`.`posts` 
        ORDER BY `date` DESC LIMIT 8;
    ") or handle_error("There was a problem getting the recent posts.", "prepare failed :".htmlspecialchars($mysqli->error));
    $stmt->execute() or handle_error("There was a problem getting the recent posts.", "execute failed :".htmlspecialchars($stmt->error));
    $stmt->bind_result($date,$title,$path,$image_path) or handle_error("There was a problem getting the recent posts.", "bind_result failed :".htmlspecialchars($stmt->error));
    while($stmt->fetch()) {
        $formatted_date = date('F j, Y', strtotime($date));
        $results .= '<a href="'.$path.'" class="recent"><h4 class="home-head">'.$formatted_date.':<br>'.$title.'</h4><img src="'.$image_path.'" class="no-border"></a>';
    }
    echo $results;
?>

With this configuration, it works. However, I am repeating the databaseConnection.php code in the homePageLink.php. But whenever I remove this code from homePageLink.php

$mysqli = new mysqli(DATABASE_HOST, DATABASE_USERNAME, DATABASE_PASSWORD, DATABASE_NAME);
if ($mysqli->connect_errno) {
    handle_error("There was a problem connecting to the database that holds the information we need to get you connected.", "Failed to connect to MySQL: (".$mysqli->connect_errno.") ".$mysqli->connect_error);
}

it does not work. The mysqli prepare fails when I remove it. But there is no error message. I can not figure out why it does not work. The funny thing is that it is working the way I want it to in other files. There is no difference aside from the queries and outputs.