fyllo, he asked for help on how to get GUEdit working...
Download java 1.1.2.1 or whatever version is newest from java.com, this lets you run GUEdit, open a copied .CHk of your map (use staredit to save as .chk (file - save as .chk) protect this, and save as a .scx file.
Another program that is good for prrotection is SCM Toolkit, this one is harder to get working but it works much better.