Getting this error constantly

I keep getting this error no matter what I do. It looks to me like map/chunk corruption. I deleted the map and made a new one, and I still get this on the new map. It usually happens when certain users connect. I'm going out of my mind trying to figure this out. Any suggestions?

http://pastie.org/7011858

 

That probably means
a) map data around their position is corrupt
b) their player.dat file is broken

Have you tried deleting the .dat of those players? Also, dynmap shows up in that crash, have you tried a test run without plugins?

 

Yes, that was my thought process too. Deleting the player .dat files resolves the issue temporarily, but the problems persist when players return to certain areas. I suspect bad chunks.

I saw dynmap in there too. When I removed plugins, the errors did not go away. I generated a new map tonight in the hopes that the issues will be resolved, but I'm still puzzled how this happened.