that -might- be it. I'm not 100% sure, cause I'm not really a map expert xD but even if that's not the case, it's good to have a separate object group for your maps object. (Mine's just called LifeStreamObjects) Cause if you have My Trees, My rocks, etc. then give it to people, they won't be able to keep both objects from other maps that might keep default names for their objects and stuff, unless it's been fixed.
If you need help figuring how to do that, let me know. Can't remember off the top of my head x3