The R10.04 version is also affected.
Sometimes you can order a License product, sometimes not (blank page in any version, tested on official demos).
And if you hit F5 in the blank page, you order another one and it works (not a blank page, cart with 2 ordered products)
Could be related to
<response name="success" type="view-last" value="showcart" save-last-view="true"/>