Did you delete your database? How many databases are you using? If you are no longer using the 'My First PokerTracker Database' simply remove it in PokerTracker via File->Maintain Database Names and that should resolve the issue.
Ok, thats good. Enable logging, open your poker client, play 30+ hands on a 'single' table then send me the PAHud.log file via the Support system so that I can troubleshoot the issue. We will get it working properly again. :)