Can that part be replaced with one from another supplier? The supply chain logistics for gadgets like the iPad and NGP are tight enough on a good day. It's unlikely that production NGPs are being built yet as Sony hadn't locked down the final spec, but it would have been reserving all the existing parts it needed well in advance.
Anything in a warehouse might be damaged, or need to be checked out for shock damage. All these issues add up to a lot of questions that people with very long, complicated spreadsheets need to answer.
Ultimately, it is not important if the NGP makes it in time for Christmas or a few months later, but the juggling act to get things right for any launch (as shown by the Xperia Play launch troubles - and all they did was miss a boat) is a tricky task, one that becomes a nightmare when nature gets in the way.