I upgraded to the most recent version of Simple:Press today.  Everything went well and functionality seemed fine.

After a while, I then made the mistake of bulk-upgrading several simplepress plugins, and now each time a user clicks a topic of refreshes a forum page, they get an “Invalid database query” pop-up error in a green box at the top of the screen.  This happens even though it appears that everything is functioning normally.

Since I did a bulk-upgrade of the plugins, I have no clue which plugin has caused this error.