Where is this place where you're getting stuck? Are you sure that you've destroyed everything and if so, did you do it in the order that it was meant to happen?
The reason why I ask about the order of things is that even though you have destroyed the enemy, you might have missed a cutscene or something of a plot that was supposed to happen in a certain order.
Just give some more info in regards to the problem.
its the land between the sisters of battle hq and the imperial guard hq. its like a normal battle but they're so heavily fortified i cant break through their defences. and the only objective is destroy all buildings capable of creating units. ive scored the map and every corner and it still says i havent won.
i tried this on a different race and campagin and the same thing occured