Overlapping UVs

Make sure that your meshes have a 2nd uv channel with a proper lightmap Unreal Engine 4 Tutorial: 2nd UV Channel (english) - YouTube

Hello, I am playing around with a wood material on several instances of the same cabin and for all of them I am getting the same warning:
Cabin_01_name of my map Object has overlapping UVs.
Cabin_01_name of my map Lightmap UV are overlapping by 99.9%. Please Adjust content - Enable Error Coloring to visualize.

So for every cabin I have I get this same error message for each. What does this mean, is it just a warning or should I never overlap geometry that I import or place in my scenes?

Thank you again, I Love this Engine:) It reminds me of the old days using the Unreal Tournament editor and now it is sooooo much better:) I will pay $19 a month for the rest of my life for this Awesomeness…