Server crashes on player join

Hello bukkit community,

I'm getting a really annoying crash that happens once so often. It happens only when someone just joins the game, although one time it happened when an admin used the /seen command from Essentials.

What happens after they join is: console error, but surprisingly the server doesn't just stop dead. Players can still move about on the server, and use chat for a little bit, but other than that, it's just perpetual lag. Can't destroy blocks, entities don't move, etc.

Eventually after 30 seconds all players disconnect due to Java.io.socketexception: connection reset (or something like that).

Here's the full details:

Console log at the time server crashed:

http://pastebin.com/d4mfgZ1K.

Full crash report. A list of plugins can be found on Line 85.

http://pastebin.com/BPMRpw5j

Also, I'd like to point out a consistent feature in these crashes: in the console log, it's always something along the lines "net.minecraft.server.v1_5_R2.ReportedException: Loading NBT data". In Line 50 of the full crash report, "Tag name: blocks" and "tag type: 7" are always the same.

 

Try regenerating a new map. Respond if still not working.

 

I was afraid that might be the problem. I'll be doing that soon.