I just turn off the USCitiesX-LasVegas scenery any its still the same
"
Then you have *another* scenery in conflict. Assuming that with "still the same", you still see the same image as in your screenshot. As I've said, that's not the ground texture that comes with FSDT KLAS so, it must be another scenery.
Have you set KLAS on an higher layer than every other scenery that might conflict with it ? That's where the installer place it by default but, of course, if you moved it, anything can happen.