There are no official clarifications.
Official Wizards support compiled FAQs and errata for 4e D&D for download here.
Neither of the provided documents mention this ritual, so what you have is what you have.
4E was generally lighter on the combat utility of out-of-combat effects like rituals, so it's not really a surprise that you can't just make an impenetrable wall of force at level 8. You get a safe place to rest whatever the weather, but you still have to work to conceal it and keep watch.