Okay about the first answer I will get to you back on a later time since it does require some time to install.
The second answer you gave:
Those two files are in the folder you supplied. And when I open ot_gv.php in Notepad I can see this: define('TEXT_ENTER_GV_CODE', 'Enter Redeem Code '); So that means the variable is defined. But it doesn't show up during checkout.