I'm sorry to tell you this, but there is no object editor in the 3ds version.
As far as I know, this is impossible to do in level editor; it is something only the producers can do.
It takes a red object and a blue object to open the purple gate; a white object and a black object to open the grey gate.
For the last puzzle level of Scribblenauts, you don't have to write anything, just head towards the Starite and the doors will open for you automatically.
You open the wc3 folder and hit campaign editor.
Use Hex Editor.
Start > Run > Registry Editor > Windows XP
right click your wc3 icon and click open file location then in that folder that opens find world editor and open it, world editor doesnt have anything to do with clans
Open it with a text-editor.
Any text editor will do. In practice, you would usually use an IDE, which includes an editor.
Go into Doom 3, open the console by pressing CTRL/ALT/` at the same time. When it is open, type "editor" and you will go to the editor tab.
Maybe, just try it
Audacity is an open source freeware. It has many functions that you may like. Dexster Audio Editor is good.