Sorry that that add-on doesn't seem to be working and for the delayed response.

I tried to create an account and search for a car on that website but when I went to reserve a car it didn't ask me for a credit card number, instead it said I would have to show a credit card when I went to pickup the car so I doesn't look like I'll be able to see what is going wrong on that website, sorry. Anyway thanks for taking the time to download the add-on, try it, and write a review.