If I were you, then I would talk to my dean and the program coordinator (not program director lolz) for my home department about this ASAP. Well.. I guess you need to tell them anyways.
If they are not helpful, then I will apply to 2 or 3 random programs that I have absolutely no interest in going. On Monday, I would call that 2 - 3 programs and ask the same question to their program coordinators. If they act like it isn't a big deal, then you can probably explain as you interview if it comes up. If they act like it is something that needs to address immediately, then I will send email or call the program coordinators for all the programs that you previously applied to.
I am sure they dealt with all sorts of crazy things for who knows how many years. It could be something that program would overlook (because 99.9999% people don't apply one year earlier/later), or it would be comparably easy fix, if you tell the program coordinator.
Again, it is just my suggestion, and I did not hear about anyone who had similar problem. I feel your pain, and I would be freaking out too!! But, at the same time, I think it is just minor mistake that human being could make. I am sure that most programs will understand. Good luck!