Heyyo,
I'm guessing you we're following these instructions:
http://rcbot.bots-united.com/forums/...showtopic=1374
If so and you get "No valid signature?" You need to right-click the game in your Steam menu and then go to "Properties". From there you go into "Set Launch Options". In the launch options you need to set..
And that will disable signature checks and let RCbot load.