Are they in %localappdata%/Activision/CoDWaW/mods (which is C:/Users/USERNAME/AppData/Local/Activison/CoDWaW/mods) ?

Is your game updated to 1.7 if you're using disc version? (Steam should be fine.)

there two call of duty folders on your pc

you must place the custom maps in the one located in users/appdata

not programfiles - this one is for "making" mods

in "appdata" not the call of duty folder in program files