In fact the process is the following :
choose a zone
choose a npc
write something in the editor
save
the buttons become enable when u press a key in the editor and if a npc and a zone has been selected before.
the goal of this is to do for you the choice of the quest file where you save the script. so, people don't save quest files everywhere on their harddisk and wonder why it doesn't work in the emu
Edit : tho, i have nothing against adding an 'expert mode' with a file selector and permanently available save/reload buttons