The wording on this card says [special Action] Choose a space within 3 spaces and roll 1 red die. Each Figure on or adjacent to the chosen space suffers [damage] equal to the [damage] results.

Does this mean that the figure using this card can choose a space on the other side of a closed door or through a wall? Im having trouble finding a rule that says otherwise.

-S

No, you cannot count spaces through a door or a wall.

"Counting Spaces", RRG, Page 9:

Many effects require players to measure the distance between two spaces. To determine this number, the player counts the number of movement points it would take for a figure to move from one space to the other.

Impassible terrain, figures, and difficult terrain can be moved into and through without costing additional movement point for this measurement. This measurement cannot go through walls, doors, or blocking terrain.

Basically from what we've seen there is no ability or command card that allows any sort of movement or use of spaces on the other side of a wall or door.