Just name the collision mesh as Col. Also, I'm attaching the file, should work hopefully.
http://www.mediafire.com/?bhh773ab7njhufb
Crashes
if it helps at all, I get 5 warnings upon export
Exporting...
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Warning: bone node "Bone" (Blender Object:Hub2) conflicts
with existing bone node name "Bone" (Blender Object:Hub3) !
Changed name of bone node to: "Bone(1)"
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Warning: bone node "Bone" (Blender Object:Hub1) conflicts
with existing bone node name "Bone" (Blender Object:Hub3) !
Changed name of bone node to: "Bone(2)"
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Warning: bone node "Bone" (Blender Object:Hub0) conflicts
with existing bone node name "Bone" (Blender Object:Hub3) !
Changed name of bone node to: "Bone(3)"
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Warning: bone node "Bone" (Blender Object:Mount1) conflicts
with existing bone node name "Bone" (Blender Object:Hub3) !
Changed name of bone node to: "Bone(4)"
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Warning: bone node "Bone" (Blender Object:Mount0) conflicts
with existing bone node name "Bone" (Blender Object:Hub3) !
Changed name of bone node to: "Bone(5)"
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