I've just uploaded Poker Sleuth 2.1.0.17, which includes additional diagnostics.  It also includes a few bug fixes, so it's possible that it will simply solve your problem.

Assuming it doesn't solve the problem, here are instructions for accessing the additional diagnostics.

The HUD tab now lists all windows belonging to the poker client, not just table windows.  Existing windows will not be detected until you click in them at least once.

In the HUD tab, if you right click on a window's name and select "Details", a window will show up with diagnostic information (basically, all of the information Poker Sleuth uses to determine if a window is a table or not).  Copy the information to the clipboard and send it to me (after removing any personal information as you see fit) so I can puzzle out what's going awry.

If Poker Sleuth doesn't list any windows at all for the poker client, please submit a new stderr.log (as the new version may record additional information there as well).

Thank you for your patience. :-)