My problem is that by my map I built the floor gets black when you shot. I need help.
yea that'd be a glitch. i hate it when that hapens. first, make sure it isn't a shader (for some reason that breaks up the when shot on ground some times) second, i dunno.
could be a overlapping brushes or an uneven surface. Check all your brushes vertices. And not only the verts of the messed brush, but _all_ verts. ;)