Try changing line 96 of WA_DigitalFilePro\HelperPHP.php file:
$theCopy = move_uploaded_file($uploadedFile["tmp_name"], $tmpFirstFilePath);
to:
chmod($uploadedFile["tmp_name"], 0777);
chmod($tmpFirstFilePath, 0777);
$theCopy = move_uploaded_file($uploadedFile["tmp_name"], $tmpFirstFilePath);
and 98:
$theCopy = copy($firstFile , $tmpFileNamePath);
to:
chmod($firstFile, 0777);
chmod($tmpFileNamePath, 0777);
$theCopy = copy($firstFile , $tmpFileNamePath);