Same problem.
 

Today i ran into the same problem that i had months ago with ACM2.4.
At one point in the game everything stops working.
For example i click on a ship and i get " yes sir " then i move the cursor to another ship but as i do that the first ship is no longer under my direct command. The damage bar is not visible anymore so i can't give it any commands.
On the galactic map i can still move from system to system but what is the use if tactical won't work ?
Again What is going on here ?:confused::confused::confused::confused::confused ::bawl:
That is also why i can't ever seem to finish this game.
I just found out that the GUIDialoge.xml file has a syntax error according to my computer, the only problem with that is that i cannot find that file anywhere.