The server does indeed crash on a map rotation. The only thing I can think of is that the Fort Rhuin map was updated recently and may be causing the crash. I'm not sure who's in charge of NA_2 but we could help you identify which map is causing the crashes if we had a map list of some sort.
BTW NA_2 is still down, has been all day. Playing on battle is too depressing for me, please revive siege soon!.