NPCScan Cache Remover is a .bat file that will delete your creature cache file. It runs checks to determine 32 or 64 bit clients, then checks to see if WoW is already running. It checks and reports at each step what it has found and will tell you whether or not it has cleared the cache.
There's a new file posted as beta under Other Downloads that should work alongside the new Battle Net app. If you haven't launched WoW yet, run the wow.bat file and it will clear the cache. If you're in game and need to clear the cache, exit the game, run the wow.bat file, then hit the Play button in the app.
Repackaged to a .zip file.