Not to step on 's toes here, but I think this may be related to a bug I’ve already entered that can cause the import to get stuck in this if you select and unselect certain check boxes for the Skeletal Mesh and mesh options.
The resolution to “reset” this on the other users project was to delete the saved and intermediate folders in the project folder. More than likely you’ll only need to delete the config folder, but if that doesn’t work try both. (Make a copy of these if necessary). Once that’s done start up your project and see if the mesh will import.
Tim