someone tell me, why i cant use Number 78's eff?
i think i didnt do some mistake.
opponent battle phase, i SS battle fader + rainbow kuriboh. after that in my turn, i overlay the to summon Number 78 : Number Archive. but i still cant use eff even several turn passed. not respon in chain activation and cant be actived in my turn. othey way to summon Number 78 i did but still cant use eff.

but i can use eff easly if i duel with al(bot) and can respon in chain activation. but, al(bot) didnt chose at random

anyone can tell me WHY?