I just registered my digital copy of the game, and have tested installation.

Great Atari games are 50% off with code: atari50

The only version this deal works with is the special SYFY edition - So I'm guessing it's a mistake

Goto Atari.com
Select Games
Select PC Download

Change the list view for Show All because it's near the end of the list several pages down and there's lots of other good stuff

I've tried the code on the following:

Star Trek Online SyFy Edition = $25
Ghostbusters = $10
Champions Online $10