yes and this part will have to change to:

//Redirect to API and back to store front

$redirectTo = "https://dart.fine-art.com/api/process.asp" .
"?userID=" . $userID . "&password=" . $password . "&action=" . $action .
"&artistFirstName=" . $artistFirstName . "&artistLastName=" . $artistLastName .
"&price=" . $price . "&title=" . $title . "&category=" . $category . "&urlArt=" .
$urlArt . "&vendorCode=" . $vendorCode . "&subject1=" . $subject1 . "&subject2=" . $subject2 .
"&media1=" . $media1 . "&urlReturn=" . $urlReturn . "&paypalEmail=" . $paypalEmail .
"&watermark=" . $watermark ;