Can you provide more information on how you are uploading the object?
Are you generating normals in tab 1 and in tab 2, when you upload are you choosing to upload the physics from the file or are you setting the physics level using the drop down levels, if the second option, what level are you setting them at?
Also, you might want to check out the following link:http://opensimulator.org/wiki/Collada_Mesh#Phantom_mesh
Mesh works a bit differently here than in sl. For example, never use steps one and 2 in the physics tab on upload.