If she's using a custom tileset and you do not have that same one, then you'll get a really funky looking map if you use a different tileset. If you don't have the same tileset, get it, then import into the resource editor and set the maps that USE that tileset with that tileset. You can set what maps use what tilesets by right clicking on the map, clicking on map properties, then selecting the tileset from the drop down menu in there. Also, custom tilesets require some setting up with passability and priority.
Though as I said before, you just need to import or copy/paste the Maps from her data folder into your data folder.