Is it wrong to participate in churches that feature displays of prophecy or "spells" to ward off evil?
Anytime a Christian seeks for miracles and signs rather than for God's word they are moving in a dangerous direction. The church has always been subjected to false teachers promising personal revelation and performing signs. The Bible warns about these evil men, in particular:
2Pet. 1:20 But know this first of all, that no prophecy of Scripture is a matter of one’s own interpretation,
2Pet. 1:21 for no prophecy was ever made by an act of human will, but men moved by the Holy Spirit spoke from God.
2Pet. 2:1 But false prophets also arose among the people, just as there will also be false teachers among you, who will secretly introduce destructive heresies, even denying the Master who bought them, bringing swift destruction upon themselves.
2Pet. 2:2 Many will follow their sensuality, and because of them the way of the truth will be maligned;
2Pet. 2:3 and in their greed they will exploit you with false words; their judgment from long ago is not idle, and their destruction is not asleep.
The Apostle John also warned about those who try to fool believers by their signs and prophecy:
1John 4:1 Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world.
1John 4:2 By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God;
We should avoid such people and seek the word of God. When we become students of God's word, we are taught by the Spirit to discern good from evil and press on to spiritual maturity (Heb 5:13-14).