"Uncaught SyntaxError: Unexpected token <" when using rename() function

With PHP I am trying to move a picture from one folder to another. In my photo processing script, when I use rename(), I get the following error message in my console:

Uncaught SyntaxError: Unexpected token <

My rename function is something like this for example:

rename("../../uploads/temp/users/15/photo-user-15-2015-01-31-13-19-12.jpeg", "../../uploads/final/users/15/photo-user-15-2015-01-31-13-19-12.jpeg");

I already changed the permissions for the folders "temp" and "final" to 777, but still I get this problem.

Here comes my full code:

<?php

/************************************************
 * The Croppic Img Crop To File PHP
 * - goal: cropping the image
 ************************************************/

/* saves cropped image to "temp" folder
* possible GET parameters:
* - subfolder  -->  contains name of group: users, adverts
*/

session_start();

include '../db.php';
include '../functions.php';

// receive image data
$imgUrl = $_POST['imgUrl'];
$imgInitW = $_POST['imgInitW'];
$imgInitH = $_POST['imgInitH'];
$imgW = $_POST['imgW'];
$imgH = $_POST['imgH'];
$imgY1 = $_POST['imgY1'];
$imgX1 = $_POST['imgX1'];
$cropW = $_POST['cropW'];
$cropH = $_POST['cropH'];

// set image quality
$jpeg_quality = 100;

// define output name
$folderUploads = '../../uploads/';
$tempParentDir = $folderUploads . 'temp/' . $_GET['subfolder'] . '/';
$finalParentDir = $folderUploads . 'final/' . $_GET['subfolder'] . '/';

// if user folder does not exist create one
$parentDirWithUserFolder = $tempParentDir . getUserId($db);
if (!is_dir($parentDirWithUserFolder)) {
    // Check if the parent directory is a directory
    if (!is_dir($tempParentDir)) {
        die('Invalid path specified');
    }
    // Check if the parent directory is writeable
    if (!is_writable($tempParentDir)) {
        die('Unable to create directory, permissions denied.');
    }
    // Create the directory
    if (mkdir($parentDirWithUserFolder) === false) {
        die('Problems creating directory.');
    }
}

// make sure only specific types of images get uploaded
$what = getimagesize($imgUrl);
switch (strtolower($what['mime'])) {
    case 'image/png':
        $img_r = imagecreatefrompng($imgUrl);
        $source_image = imagecreatefrompng($imgUrl);
        $type = '.png';
        break;
    case 'image/jpeg':
        $img_r = imagecreatefromjpeg($imgUrl);
        $source_image = imagecreatefromjpeg($imgUrl);
        $type = '.jpeg';
        break;
    case 'image/gif':
        $img_r = imagecreatefromgif($imgUrl);
        $source_image = imagecreatefromgif($imgUrl);
        $type = '.gif';
        break;
    default:
        die('image type not supported');
}

$pathForDb = getUserId($db) . "/photo-user-" . getUserId($db) . "-" . date('Y-m-d-H-i-s');
$output_filename = $tempParentDir . $pathForDb;

$resizedImage = imagecreatetruecolor($imgW, $imgH);
imagecopyresampled($resizedImage, $source_image, 0, 0, 0, 0, $imgW, $imgH, $imgInitW, $imgInitH);

$dest_image = imagecreatetruecolor($cropW, $cropH);
imagecopyresampled($dest_image, $resizedImage, 0, 0, $imgX1, $imgY1, $cropW, $cropH, $cropW, $cropH);

imagejpeg($dest_image, $output_filename . $type, $jpeg_quality);

// move photo file from temp folder to final folder
$sourcePath = $output_filename . $type;
$finalPath = $finalParentDir . $pathForDb . $type;
rename($sourcePath, $finalPath);

$response = array(
    "status" => 'success',
    "url" => $output_filename . $type
);

print json_encode($response);

?>

This script works perfectly when WITHOUT the rename function.

Here comes the response the file provides under "Network":

<b>Warning</b>:  rename(../../uploads/temp/users/15/photo-user-15-2015-01-31-13-41-26.jpeg,../../uploads/final/users/15/photo-user-15-2015-01-31-13-41-26.jpeg): No such file or directory in <b>/home/www/system/process-image-upload/process-image-save-to-temp.php</b> on line <b>94</b><br />

The file definitely exists, i looked it up on the server. I use rename($value1, $value2)...