Arcexplorer seems to create an empty .map file.
Try GrimArc instead!
It’s a CLI utility, no UI, but it works …
Open a shell, change to the folder where the levels.arc is and then type “GrimArc levels.arc”.
A new folder “extracted” will be created with the world001.map in it.
Edit: I replaced the “Debug”-version with the “Release”-version for those, who don’t want to compile the project itself.