That file should have already been there, you simply need to overwrite what's inside of it.

Well, I have yet to do a single update with Diablo.

I'm going to reflash either tonight or tomorrow along with all of the upgrades and post back here in a day or so to see if there's anything that might be causing your troubles.

Worse case would be that you will have to go through the entire mapper.txt file and change the keys to your settings.

It would be really nice though if Pushwall posted back here since he clearly knows his junk more than me.