Hey, I've been trying to run a server that I've had no problem running before until I updated the server software. Now I get THIS every time I attempt to connect (taken directly from the server logs)

11:35:14  Setting up
     11:35:14  Loading level
     11:35:24  Now accepting input on 1097
     11:35:29  Level saved! Load: 0/16
     11:35:29  To connect directly to this server, surf to: http://www.minecraft.net/play.jsp?server=71566aa769d1f553229bf23546e725e8
     11:35:29  (This is also in externalurl.txt)
     11:36:29  Level saved! Load: 0/16
     11:36:56  /127.0.0.1 connected
     11:36:56  /127.0.0.1 logged in as Creaper11
  !  11:37:02  Creaper11 (/127.0.0.1):java.nio.BufferOverflowException
  !  11:37:02  Exception handling Creaper11 (/127.0.0.1)!
  !  11:37:02  Creaper11 (/127.0.0.1):java.lang.NullPointerException
  !  11:37:02  Exception handling Creaper11 (/127.0.0.1)!
     11:37:02  Creaper11 (/127.0.0.1) disconnected
     11:37:29  Level saved! Load: 0/1

I'm attempting to load a map with the dimensions 1024x3 (which I've had
no previous trouble doing at all)

I made the map in z0mg map editor and I have a feeling this is the problem because when someone else tries to host we get the exact same message (they use the same map file). We also get the problem whenever someone tries to join externally.

Please suggest ANYTHING that could be the cause of the problem, i've tried clearing the Java cache to no avail, and i'm seriously running out of ideas here.

Oh, and I'm able to join any other server with any other map size.