[ODE] Weird Trimesh assertion

[O'dell Hicks]

For some weird reason, I'm getting an assertion on some collisions for
trimeshes

asertion "Index >= 0 && Index < (Flags & 0x0ffff)" failed in
....collision_trimesh_internal.h:96

Here's my setup:

dVector3* _collVertices = new dVector3[numVerts];
int* _collIndices = new int[numIndices];

dTriMeshDataID Data = dGeomTriMeshDataCreate();
dGeomTriMeshDataBuildSimple(Data, _collVertices, numVerts, _collIndices,
numIndices);
_geom = dCreateTriMesh(space,  Data, 0, 0, 0);

I did a test to make sure that numIndices was always >= 0 and < numVerts, so
even if collVertices had junk data, the indices should be fine.  Also, these
arrays are not being deleted until after the geom is destroyed.

Any ideas on what I may be doing incorrectly?