For those who just want to play the game through CKAN - Go to the Game Directory > CKAN and open up GUIConfig.xml. Under "CheckForUpdatesOnLaunch", set it to false. Relaunch CKAN and you'd still get an error, click "Continue". You should be able to run KSP from there. You can still uninstall mods but keep note that it'll throw out an error for every click - but you can just click Continue to keep skipping it.