Small error in the filepath fixed.

classes/upload.class.php

         $randomname = Upload::generateRandomString(); // We give our file a random name - It will be this.
 
         $cwd = getcwd(); // Our websites CWD (Current working dir)
-        $uploadPath = $cwd . Config::$file_path . $randomname . '.' . $extension;
+        $uploadPath = $cwd .'/'. Config::$file_path . $randomname . '.' . $extension;
 
         if (!in_array($extension, Config::$file_types)) {
             // Error! This file does not have an acceptable filetype