basic_example shouldn't work out of the box ?

1. file_upload.php
   line 2: require(dirname(FILE) . '/../../Uploader.php');
   isn't "Uploader.php" location in the "extras" folder?

so modified line 2: require(dirname(FILE) . '/../../extras/Uploader.php');
and fixed the first error

2. after fixed problem (1) , I set "debug: true" in index.html
   now when i try to upload a 100kb jpg I have this error in the console:
   [Uploader] Server response: {"success":false,"msg":"Upload directory does not exist"}

I have created a subfolder called "upload_files" in the "basic_example" folder. give it a chmod 777 to make it writeable for anyone.

yet the error remain, after progressbar is 100% , I get "Upload directory does not exist"

also checked my php.ini tmp upload folder path, then checked if is writeable, all is ok. tested Plupload http://www.plupload.com/ , on the same server, created an upload folder with chmod 777 and it's working perfect out of the box.
No idea why Simple-Ajax-Uploader is not uploading files. My webserver is Apache, CORS is enabled in the httpd.conf on www folder. Using PHP 5.6. Browsers used: IE11, Firefox 38.