There was an incompatibility between version 2.5.1(+) and version 1.0.0 of the plugin when using the SQLite driver. this stemmed from the (new) use of index hinting within wp.
The bug manifested itself by the unavailability of any comments within the Manage->Comments screen in the admin interface. See http://rathercurious.net/archives/30 for more details.
I have fixed this incompatibility and uploaded the fix as version 1.0.2 of the plugin.
Your feedback would be appreciated.