trying to load it with /atmo only returns "Error : no atmosphere found"

wondering if it was broken by an update at some point, or if it's just me

My atmosphere do you mean shaders? Because shaders are now built into the main menu.

Main menu > Setup > Utils > Shaders

Then there will be a large list of shaders.

Atmosphere should work, I believe it was built into the game a while back. If it doesn't work, install the script here:http://forum.toribash.com/showthread.php?t=162608

As for if it's broken and just doesn't work anymore, I'm not quite sure. It was working on stand-alone version 5.11, last time I checked. Once I get home I'll check for you and run a little test

I just tested the link that Karbn provided and that was working well. I tested in most recent Steam's Toribash version and also in Toribash 4.7 version, which I already had installed here. I tested every single atmo and everything was pretty fine.
Also, I tested the most recent version in low and high graphics and 4.7 only in high graphics.

Anyways, here you can find every Toribash version, so you can download another if you need or feel like.

thanks for the responses.
i tried reinstalling the script from the download, and still get the same error. i'm going to try reinstalling the whole game and see if i get anywhere with it.

EDIT: i reinstalled toribash and i get the same error.

on to old versions!

EDIT 2: works in non-steam 5.1 version.

EDIT 3: well i fixed it. all i can guess was the configuration file i kept between installs