The TableTracker servers only provide which tables are available and who is playing at those tables. The actual table and player statistics are retrieved from your local database. If you have not imported many hands into PokerTracker then you more than likely do not have previous stats from players at the table and no stats can be displayed.
On a few sites, for the table opening functionality to work you must launch the poker site from within TableTracker. In the TableTracker window, on the bottom-left hand side click the 'Configure' button. Under the 'General' tab -> Launch Settings, choose your site, click 'Add' then browse to and locate your poker sites file used to open the site. Once configured, click 'Launch Site' from within TableTracker then you should be able to open tables.
The 'Avg Score' projects the profitability of the specific table. The higher the score, the more profitable the table should be.
The score is calculated by a complex algorithm which is based on the table players style of play. A lot of research was put into creating this scoring algorithm and we believe it is the most accurate predictor of a table's profitability available. If you would prefer to create your own scoring algorithm, you can do that under the 'Configure' button.