On file \components\com_virtuemart\views\orders\tmpl\details.php there is a missing </div> at the bottom, it should be the last line.
That missing closing div tag totally screws the layout. It can be seen in the customer order details, from list orders.
Edit: VM 2.0.2.
I have the same issue with VirtueMart 2.0.4 on Joomla 1.5.26. Added the </div> and it corrected the issue.