Go back out into the hallway, drop all of the ingredients on the ground, have your hero pick them up again and return to the summoning room. Infrequently the game can not recognize you have a particular item, but dropping it and picking it back up again should be enough to fix that. A few people have run into this issue with the first summoning test, and it can also occur sometimes if you find a quest item before getting the relevant quest.
The game checks for the ingredients as you go through the doorway from the hallway, and you should see an experience point message scroll up the screen when if it finds them, after which the instructor will respond properly.
