The nails are in correctly. We have had several people take a look at this and said that is not the problem, but they can't figure out what is causing this to buckle. We're trying to work with the company now, but with all of everyone's help here in the For'em, I wanted to have some ammo because I know the manufacturer is going to say there's not a problem with the siding the the installer is going to say it's not his fault. Thanks for all the help.