Try exporting with EVERYTHING unchecked and see what happens. I did a test awhile back where someone was complaining about unwelded meshes. I found that if the check box to include group names was checked, the mesh exported unwelded, but if unchecked, it exported as a single mesh. I checked by importing into Blender and Wings 3D.

If I had a nickle for ever time a woman told me to get lost, I could buy Manhattan.