I have had the same issue, but have resolved this by copying the virtuemart theme from the gk_yourshop_rest_files_J!15 download. The issue exists if one does a fresh custom install.
[SOLUTION]
I renamed the folder ./components/com_virtuemart/themes/default and then copied the folder ./gk_yourshop_rest_files_J!15/vm_theme/default to the themes directory.
This caused my virtuemart shop to display correctly including the cart items.