You need the root, a spider leg, the summoning book, the potion from the mage Markhuntar (Feynur), wisdom rune from the rune room in Act 4. Do you have the rune from Act 3? This might mess up, drop that one.
Drop everything in the main corridor, then pick up one by one and move it in your inventory. If the log turns red, it's ok. Then turn around and run into the small front room => do XP flutter up? Then the instructor will acknowledge. Talk to him first, he will take the wisdom rune.
