Wonderful contribution, and by the looks of the updates, etc..., your continued work is remarkable.
My installation was smooth and simple. I found one misprint in my own work that was causing a error on the admin pages, but fixed that with a simple re-paste.
I have a problem on the admin->catalog->discount coupons page. The "Button_New_Coupon.gif" is not present, and with that, I cannot add a coupon to test the completed installation.
I have looked for the code that presents the "button" on the admin/includes/coupons.php, and found the code for that command, but that is as deep as I know how to dig.
What could I send you to help?