I got an email from a flunky at LiveNation. He told me the error about adjacent seats means there are no more promotional tickets left for that show.
You would think the error message would read something like "There are no more promotional tickets left for this show date" or something.
Aside from that, what the hell was that error message about "adjacent seats"??? These are LAWN TICKETS.
God damn those people at LiveNation are a bunch of idiots.