[Arryn]

Now that I have the battlefield grid turned on ('g' key for overlay on terrain, 'w' key for white grid on black background with no terrain graphics), I can see that it is 28 squares wide by 58 long. If you leave units in the default "center" of your side, with range=25 spells you cannot reach units at the default "center" of the enemy's side, which is 29 units away. And the AI tends to place its units nearer to the rear than to the front, from what I've seen. Also, from the center of your side, you cannot use a range=40 spell to hit units at the far back of the enemy position, which is roughly 43-44 away.

So you need to move casters closer to the front than the default start spot, or use range=100 spells.

Just some observations.