I don't know the names of the Zone tilesets, but this is what the script should look like to add a tiledef to your level.
NPC Code:
addtiledef image,levelstart,type; specifys the tiles images for all levels that start with 'levelstart' (0-standard type,1-new order)
Example:
NPC Code:
//#CLIENTSIDE
if (created) {
addtiledef pics1.png,mylevel.nw,0;
}
First you specify the image name, then the level name, then the type. For tilesets like Era's the type is 1 and for tilesets like the default (pics1.png), it's 0. For the level name, you can put what the level's filename starts with if you wish to. What I mean by what it's starts with, is like if my level is named 'skrobo-level.nw', I could put just 'skrobo-', instead of the full file name. Then I could use the same script for every level that starts with 'skrobo-'. Hope this helps.
You can't use GS2 in the level editor, but I'll put the way it should look in GS2 just for anyone that may want to know.
GS2:
NPC Code:
//#CLIENTSIDE
function onCreated() {
addtiledef("pics1.png","mylevel.nw",0);
}