The Turn Button Anomaly... You basically have a few options.
1) Save the game, quit, then rerun TA and reload your game. Open debug.err before rerunning TA though. It makes a new file everytime you run the game.
2) Try clicking on some of your ships. Sometimes a ship has movement left but the game engine is caught up in something else. If you can find the ship with movement left, and move it, it sometimes fixes it.

Personally, I always quick-save (ctrl+S) before I click the 'End Turn' button. For the few times it happens, it saves some hassle of figuring out what's wrong.