If you see this error message and restarting PokerStars did no resolve your issue then try these solutions:
Solution 1 - Running an old version of PokerStars
You might be running an old version of PokerStars, to resolve this issue simply force update PokerStars or re-install the client.
Solution 2 - Running multiple instances of the applications
You might be running two instances of either PokerStars or Jivaro. To resolve the issue please go to 'Task Manager' search for any PokerStars or Jivaro instances running and shut them down.
Now try running both applications.