A warning displays after trying to load a custom map

I created a custom map like it's described here http://steamcommunity.com/sharedfiles/filedetails/?id=385814354 to find Maxwell's door quicker.

Now everytime when I try to load the map, this happens http://steamcommunity.com/sharedfiles/filedetails/?id=794204350 .

I have no idea why it happens, can someone maybe help me?

Thanks in  advance.