ODE INTERNAL ERROR 1: assertion "(nMinX < nMaxX) || (nMinZ < nMaxZ)" failed in dCollideHeightfield() [heightfield.cpp]
Stacktrace:

  at (wrapper managed-to-native) Ode.NET.d.Collide (intptr,intptr,int,Ode.NET.d/ContactGeom[],int) <0x00004>
  at (wrapper managed-to-native) Ode.NET.d.Collide (intptr,intptr,int,Ode.NET.d/ContactGeom[],int) <0xffffffff>
  at OpenSim.Region.Physics.OdePlugin.OdeScene.near (intptr,intptr,intptr) [0x0010d] in /home/sdague/code/opensim-svn/OpenSim/Region/Physics/OdePlugin/OdePlugin.cs:400
  at (wrapper native-to-managed) OpenSim.Region.Physics.OdePlugin.OdeScene.near (intptr,intptr,intptr) <0xffffffff>
  at (wrapper managed-to-native) Ode.NET.d.SpaceCollide2 (intptr,intptr,intptr,Ode.NET.d/NearCallback) <0x00004>
  at (wrapper managed-to-native) Ode.NET.d.SpaceCollide2 (intptr,intptr,intptr,Ode.NET.d/NearCallback) <0xffffffff>
  at OpenSim.Region.Physics.OdePlugin.OdeScene.collision_optimized (single) [0x000f6] in /home/sdague/code/opensim-svn/OpenSim/Region/Physics/OdePlugin/OdePlugin.cs:923
  at OpenSim.Region.Physics.OdePlugin.OdeScene.Simulate (single) [0x0022c] in /home/sdague/code/opensim-svn/OpenSim/Region/Physics/OdePlugin/OdePlugin.cs:1600
  at OpenSim.Region.Environment.Scenes.InnerScene.UpdatePhysics (double) [0x0000d] in /home/sdague/code/opensim-svn/OpenSim/Region/Environment/Scenes/InnerScene.cs:165
  at OpenSim.Region.Environment.Scenes.Scene.Update () [0x00148] in /home/sdague/code/opensim-svn/OpenSim/Region/Environment/Scenes/Scene.cs:701
  at OpenSim.Region.Environment.Scenes.Scene.Heartbeat (object,System.EventArgs) [0x00000] in /home/sdague/code/opensim-svn/OpenSim/Region/Environment/Scenes/Scene.cs:646
  at System.Timers.Timer.Callback (object) [0x0005e] in /home/sdague/mono-build/mono-1.9/mcs/class/System/System.Timers/Timer.cs:185
  at (wrapper runtime-invoke) System.Object.runtime_invoke_void_object (object,intptr,intptr,intptr) <0xffffffff>

Native stacktrace:

	mono [0x8171bda]
	[0xb7eeb440]
	/lib/tls/i686/cmov/libc.so.6(abort+0x101) [0xb7cada01]
	./libode.so(dDebug+0x3a) [0xb460bc4a]
	./libode.so(_Z19dCollideHeightfieldP6dxGeomS0_iP12dContactGeomi+0x803) [0xb4611f63]
	./libode.so(dCollide+0x241) [0xb45fdc61]
	[0xb2da6082]
	[0xb2da4dbc]
	[0xb4a53492]
	./libode.so [0xb4602119]
	./libode.so(_ZN11dxHashSpace8collide2EPvP6dxGeomPFvS0_S2_S2_E+0x7d) [0xb4603b0d]
	./libode.so(dSpaceCollide2+0x180) [0xb46022a0]
	[0xb2da49a7]
	[0xb2da484d]
	[0xb39f0577]
	[0xb67f2fd7]
	[0xb40fbf6d]
	[0xb40fbbc4]
	[0xb40fbb3b]
	[0xb63092ae]
	mono(mono_runtime_invoke_array+0x433) [0x80e20b3]
	mono [0x80e279d]
	mono [0x80d4ff3]
	mono [0x80d66bd]
	mono [0x809f5df]
	mono [0x810ab72]
	mono [0x812e065]
	/lib/tls/i686/cmov/libpthread.so.0 [0xb7dfa4fb]
	/lib/tls/i686/cmov/libc.so.6(clone+0x5e) [0xb7d57e5e]