As explained so many times on the forum, whenever you see problems placing the airplane, it's never a fault of the airport, and it's always a conflict caused by another AFCAD coming from another product.
Usually, those offending sceneries are those supplied with AI Traffic products, like MyTraffic, which are supposed to be used only if you have the default airport, but will cause double objects and problems if you have an addon airport, so they must be removed.
Either find a .BGL file with a name that seems to be related to KLAS, or use the Simple Airport Scanner utility, to help you find conflicting files.
http://www.scruffyduck.org/simple-airport-scanner/4584282795