Now import button will check if object is mesh type and leave other untouched.

io_coat3D/coat.py

@@ -290,6 +290,7 @@ class SCENE_OT_import(bpy.types.Operator):
         test = bpy.context.selected_objects
         act_first = bpy.context.scene.objects.active
         for act_name in test:
+            if act_name.type == 'MESH':
                 activeobj = act_name.name
                 mat_list = []
                 scene.objects[activeobj].select = True