Vertical Scroll not refreshing the size of the page

[Dujardin store]

Hello,

I'm a newbie so let me know if i am not clear enough.
the site is www.dujardinstore.com for the prod and
dujardin.bluevision.be for the dev.

The process is as follow:
1. when you load first, you have the default navigator scroll bars. I
try to use the technics in different posts on this group but cannot
figure them out. I need help.

2. try Femmes/Women and then make some buyings more than 3 and then go
check out. You do the 4 steps (select a card from the payment solution
-- you will not be asked for a number) and then appears the
summary.... I cannot place my orders.. the page cannot go below.

I have other examples. the thing I see is that the top of the scroll
pane cannot go below height: -196px what ever is the content of my
page.

So basically i have this error on all IE, Safari, Firefox (Mac and
Windows). It appears to be less frequent on Firefox.

What can I do?

I try the bind function but I do not understand really well the
parameters to set up.

Thanks Fred