Booking hangs after applying coupon code

Hi

I have installed 0.8 and everything seems to work fine. Only when I try to use coupons there seems to be a problem. When I reach the step for payments etc and pres next - the website just hangs. If I remove the coupon code - then everything works fine again.

Any idea what this could be?

Edit: I have found that this only happens when using 100 percent! If I use 99% or when I pick a fixed amount, then the coupon works as it should.

Is this the wrong place I asked this question - or does nobody know this?

Could someone please test if they see same problem ?

Thanks.

Anyone?

Thankyou for answer. Can you very short guide me to how I troubleshoot this ? Can I monitor a log and turn on some debugging?