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) <0x00066>
  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 () <0x00074>
  at OpenSim.Region.Physics.OdePlugin.OdeScene.Simulate (single) <0x00123>
  at OpenSim.Region.Environment.Scenes.Scene.Update () <0x00215>
  at OpenSim.Region.Environment.Scenes.Scene.Heartbeat (object,System.EventArgs) <0x0000b>
  at System.Timers.Timer.Callback (object) <0x002a6>
  at (wrapper delegate-invoke) System.MulticastDelegate.invoke_void_object (object) <0xffffffff>
  at (wrapper runtime-invoke) System.Threading.WaitCallback.runtime_invoke_void_object (object,intptr,intptr,intptr) <0xffffffff>

Native stacktrace:

        mono [0x81ab4d7]
        mono [0x818e960]
        [0xb7f55440]
        /lib/i686/nosegneg/libc.so.6(abort+0x101) [0xb7d3e4e1]
        ./libode.so(dDebug+0x38) [0xb4b04d3c]
        ./libode.so(_Z19dCollideHeightfieldP6dxGeomS0_iP12dContactGeomi+0x863) [0xb4b39323]
        ./libode.so(dCollide+0x10c) [0xb4b077c8]
        [0xb3d10e63]
        [0xb3d10b6f]
        [0x8fe3597]
        ./libode.so [0xb4b0dcbc]
        ./libode.so(_ZN11dxHashSpace8collide2EPvP6dxGeomPFvS0_S2_S2_E+0x69) [0xb4b0f249]
        ./libode.so(dSpaceCollide2+0x13c) [0xb4b0d738]
        [0xb3d10947]
        [0xb4422975]
        [0xb442253c]
        [0xb44214c6]
        [0xb4ad4c84]
        [0xb58f44df]
        [0xb58f4214]
        [0xb58f416e]
        mono [0x818e75c]
        mono(mono_runtime_invoke+0x29) [0x80b8aa0]
        mono(mono_runtime_invoke_array+0x50b) [0x80ba4be]
        mono [0x80bc65f]
        mono [0x80f5cca]
        mono [0x80f6b28]
        mono [0x80efc24]
        mono [0x8149305]
        mono [0x8162ee8]
        /lib/i686/nosegneg/libpthread.so.0 [0xb7e87482]
        /lib/i686/nosegneg/libc.so.6(clone+0x5e) [0xb7de786e]

=================================================================
Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================

Abortito