You should contact the closest US embassy/consulate and ask them. I don't think it's a big deal, but you never know. One question - I assume you turned in your I-94 tag when you checked in on your original flight? If so, did you get it back when the flight was canceled?

If you don't get a solid answer - or any answer at all - one thing you might do is route through Shannan or Dublin. You can go through US immigration/customs there, which is a heck of a lot closer than flying to the US only to run into an immigration hassle. If you get denied, at least you're pretty close to home when getting the bad news.