Welcome to the Ironworks Forums, deniser and whacky.
As for the Balor problem, consider using summons to help tank for you. Your weaker party members should be positioned as far away as possible from the Balor's spawning position, while your strongest party member summons it.
Use Free Action on your melee troops to counter the Demon's paralytic gaze, and Resist Fear to counter the Demon fear. You need +3 enchanted or better weapons to hurt the Balor by the way.