If you are using the free Zonealarm you can get the IP address where the connection attempt originated and run a whois search to find out the domain it came from (if you have the Pro version of Zonealarm, this feature is already enabled). Get the IP and go to
www.arin.net and enter a whois search (top left on page) and you get complete domain ownership info. If it appears the attempts are coming from pokerstar's servers this mystery is (probably) solved.