mesh conversion problem

I'm having a strange problem with one of my mesh/nxs entities. Basically its a level mesh created through

if (mLevelMesh == 0)
mLevelMesh = NxOgre::MeshManager::getSingleton()->load("ogre://General/Level.nxs", "level");

SceneGeometry* scene_geom = mScene->createSceneGeometry(TriangleGeometryDescription(mLevelMesh), globalPose);
mRenderSystem->createSceneNodeEntityPair("Level.mesh", Vec3(globalPose), Quat(globalPose));
return scene_geom;

The level consists of three flours with stairs leading to each of them. The top and middle level seem to work fine but the bottom level has an invisible plane over it as if the meshs first two levels were converted to nxs properly but the bottom one was converted to a cube for some reason.

The problem is shown in this video (apologies for the quality I haven't figured out how to properly work this fraps substitute but it should be sufficient to see what is going on)

http://www.youtube.com/watch?v=toGAsdj7C-0

the object is moved from the middle to the top to the bottom level showing how the robot generally is okay until at the bottom level it floats way above the floor.

I suspect it has something to do with flour. I wasn't able to use the latest version because of the mesh compatibility problem but I used an older one from Oct 2008. This is the code I used for the nxs conversion

Flour convert in:Level.mesh, into: triangle, out: Level.nxs

can anyone suggest a solution or workaround?

Stupid question, but you don't have the ground plane on do you?

Also; have you tried it with the VisualDebugger on or having a peak through it with the RemoteDebugger?