You can not only replace the map editor exe.
You need to replace the complete thing with everything inside the 116/117 update.
Also downgrading from 117 to 116 will not work, as they differ completely.
Just reinstall FPS Creator, copy over your entity/segment/mesh/texture/script bank folders out of your files and than apply the 117 update. Make sure your rename the old FPS Creator folder to something different and than just repair your installation if the setup does not want to reinstall.
Thats how I install all new updates (and also to have a backup of older versions, if the newer ones dont work that well).