Did you check your console to see what might have gone wrong?
There are lot of problems that can cause your map not to load, like maybe concave geometry with-in the map.
If you make a hole in a whole that causes the angles of the geometry in that item to bend inwords the game will not load your map because the engine can't.

last time a checked (a few erros ago) it said cant use so and so command without sv_cheats 1