The Halloween party is being held under the crying statue in the graveyard. Bring the four treasures to the ghouls gathered there. You receive 50 Poptropica credits.
Fill the lantern with kerosene in the basement. When you have all four treasures, talk to the ghost cat to the right of the kitchen.(see related question)
Collect the other 3 treasures (Chalice, Ice, and Draught) and fill the lantern with kerosene in the basement. Talk to the ghost cat, and he will send you to the graveyard.
you don't do anything with it .... until you get the other four items a vile in the basement, ice , in the freezer staff on the knights suit or next to it then you have to go up to the bedroom...