My files/folders are as follows:
maps:
mapname.bsp
mapname.cfg
mapname.jpg
mapname.map
mapname.mapinfo
textures:
mapname:
(list of custom textures.jpg)
As for the map itself, I've added the "message mapname" and "author myname" to the worldspawn.
I removed the .DS_Store files (cuz I'm on OS X), and did "zip -r mapname *", and then renamed the .zip to .pk3 in the file info dialogue.
The resulting .pk3 does not show in the map selection menu in Nex. The odd thing is that before I added the custom textures, it did show in the menu. But removing the custom textures does not help. The map no longer shows in the menu.
What am I doing wrong here?