Headers don't match problem

Open the file gravity-forms-mass-import.php in your gravity forms mass import plugin folder.

Find line 139.

Replace it with the following:

//$retarn = $csv->auto($_FILES['csv_file']['tmp_name'], true, null, ',', '"');
$retarn = $csv->parse_file($_FILES['csv_file']['tmp_name']);

What is happening is that the auto call tries to automatically find your delimiter. If you are sure your delimiter is a comma and your encasement are double quotes, do the above and it will work fine.