Which platform are you building for when getting the exception? If you're on web player try to switch to native win/mac. The problem might be related to the lack of network access in a sandboxed environment.
With regards to samples check these two:
https://github.com/KiiPlatform/KiiUnitySDKSamples
https://github.com/KiiPlatform/UnityAngryBotsKii
Happy coding!