I don't use the Windows version, but I would assume one of these:
c:\Program Files\Idle Master
c:\Program Files (x86)\Idle Master

Bah to fancy pants GUIs! CLI forever!

try running IM as an administrator?

http://lmgtfy.com/?q=run+as+administrator

Początkowo opublikowane przez Evade:

okay i idle'ed now a game for 3 hours and only 2 card drops ... lol this game has 3 cards, cant this idlemaster idle the game so that i get in 15 or 30 minutes all card drops?
would be nice :D

No, it's all controlled by Valve's servers. All Idle Master can do is lie about what game is running and automate changing them.

You can try and get the linux script working. I'm getting a warning for the BeautifulSoup module that I'm to tired to look into, but it's correctly reporting I have 0 games left. Unfortunately, since I don't have any games to idle, I can't properly test the script's functionality.

Valve changed the Badges page yesterday (or two days ago, depending on time zones) which broke Idle Master's ability to parse the data. Idle Master mistakenly claims it's a problem with cookies. To fix the problem, you need one of the updated versions of Idle Master, but I don't think any of them work under XP.

Have you updated today?
For Windows users, here's the updated https://github.com/jshackles/idle_master_py/raw/master/start.exe and https://github.com/jshackles/idle_master_py/raw/master/idle-to-ready.exe

For Linux (and presumably OSX), here's https://github.com/jshackles/idle_master_py/raw/master/Source/Idle%20Master/start.py and https://github.com/jshackles/idle_master_py/raw/master/Source/Idle%20Master%20Helper/idle-to-ready.py

Due to changes in the refund policy, you now need 2 hours of playtime before normal drop rates start. Idle Master prioritizes getting all games to the 2 hour mark before it idles individual games for cards. As of writing this, you have 1.9 hours of playtime in Natural Selection 2 which is what Steam reports you are currently playing. You are not yet at the point where Idle Master will start earning you cards.

Free-to-Play games do not give any free cards just for adding them to your library, you must spend 9$US for each drop. You do not appear to have any non-F2P games.