The main reason why you're getting that message is because the creator of the map has protected their map. They use programs, such as StarForge and ProEdit, that protect maps so that nobody else can open the map but still can play the map in StarCraft. People protect maps to prevent people from making the map unfair(rig), hide a trick they did in their map, and/or prevent other versions from being made.
About my Windows Theme:
I got my Windows theme from
WinCustomize.
The specific theme that I have is called
Darkest Foundation. It requires a free program called
WindowsBlinds.