Coupon acting weird

I enabled a coupon on my website, but it does not work really well. Sometimes just after I enter the coupon in the shopping cart it direct me directly to paypal. And honestly it is impossible to specify only one category for my coupons, or it works for every categories or it say that this coupon do not work for that kind of product or it brings me to paypal directly...

if you want to try it the coupon is: 15decogogo and the website is www.decogogo.com .

This is the print screen, the category selected is the whole store exept the category toiles d'artistes. So it should work with every products you tried on catogeries in the home page.

Ok my coupon page looks different than his, I assume he is using the mid level product and I am on starter right?

Anyway I add my coupon for 5.00 and it shows 0.00
I cant add coupons for percentage, it keeps showing me the 0.00 flat rate amount even if i erase it.
http://www.tennoutdoorsman.com/index.php/products using the outdoors category (my test product) and using coupon "facebook5"

Sometimes it wont even allow me to add the coupon. Discounts work fine tho