PokerStars released an update to their software which broke table opening in TableTracker. This will be fixed in the next release. Until then, you can do the following which will resolve the issue:
With PokerTracker closed, open "My Computer" and browse to your PokerTracker 4/Data/Bin directory.
In a default installation this is:
C:\Program Files (x86)\PokerTracker 4\Data\Bin
Locate the two files named "if1.enc" & "OpenerInterface.enc" and delete them. Now save the following files linked below to this same directory.
http://www.pokertracker.com/misc/if1.enc
http://www.pokertracker.com/misc/OpenerInterface.enc
Once saved, start PokerTracker, launch PokerStars from within TableTracker and table opening should now work.
Best regards,
Derek