can`t get it working

I keep getting this message when I go to my shopping cart
Notice: Undefined variable: same_address in C:\wamp\www\webwinkel\components\com_hikashop\views\checkout\tmpl\address_view.php on line 81

what am I doing wrong ??

That's because you apparently have a user without any address.

Just change the line:
<?php $html = $this->cart->displayButton(JText::_('HIKA_NEW'),'new',$this->params,'','var link = document.getElementById(\'hikashop_checkout_'. $this->type.'_address_new_link\'); if(link) return hikashopEditAddress(link,'.(int)$same_address.',true); return false;');

to:
<?php $html = $this->cart->displayButton(JText::_('HIKA_NEW'),'new',$this->params,'','var link = document.getElementById(\'hikashop_checkout_'. $this->type.'_address_new_link\'); if(link) return hikashopEditAddress(link,'.(int)@$same_address.',true); return false;');

in that file via FTP and the message won't be displayed anymore.

Nicolas, thank you for your answer.

Indeed that was the problem, no address, because I made a new user through the joomla controle panel.
It works now