The only cards you can activate in the Damage Step are cards that directly alter ATK/DEF, or cards that specifically say they can be activated in the Damage Step.
Call of the Haunted is certainly not one of those.
There are two different times in a battle in which you can activate cards. The first is the Battle Step, in which you can activate any cards you want (Traps and Quick-Play Spells only, of course). This happens immediately after a player says, "I'll attack X-Head Cannon with Y-Dragon Head" (etc.). This is the only time you activate Negate Attack, Draining Shield and so forth (cards that deal with attacks) - moreover, cards that deal with attacks can ONLY be activated first thing in the Battle Phase (i.e. in the first Chain).
The second time is the Damage Step, which I explained above. This time occurs AFTER you flip a monster face-up. You're well into the battle now.
There's a big complicated chart explaining an entire battle somewhere here. Someone will post a link, I'm sure. I don't know it offhand.