The Bible is clear on all of this. Curses are real and sorcery was and still is quite common place in the world.
On the subject of ghosts brought up earlier. There is tons of evidence and also biblical evidence of ghosts being a reality. Most ghosts are simply people in the second death, hell. Hell is a place of spiritual darkness and fire. This world now that we live in is Death, hell is the second Death, and in the final judgment, both hell and death shall be throw into the lake of fire.