"22:32:10.109 - Disconnected event because of exception" [NOT SOLVED]?

First problem I see:

local localplayer = hit.Parent

That's definitely not going to be a player object, it's probably going to be a character. A character doesn't have a leaderstats object to go with it. Given a part, you can check if the part's parent is a character of a player using Players:GetPlayerFromCharacter(model).

Also, hit is not defined. What is hit? And where is Player defined?

Hmm, I see a few errors, lets try rewritting the code [Keep in mind, this code has been untested, but should work];

local Debounce = true --Heres our Debounce, Debounce is used to keep the code from firing multiple times

local function Pumpkin(hit) --Here is our function [The local is optional, I just like to use it]
if hit.Parent and #hit.Parent:GetChildren() > 0 and game.Players:GetPlayerFromCharacter(hit.Parent) and Debounce then --This will check to see if hit.Parent is existant, has objects within it [Lol how doesn't it?], checks to see if the object that touched it is a Player, and does a debounce so that it doesn't fire multiple times
Debounce = false --Heres our Debounce, this'll keep the code from firing multiple times
local Player = game.Players:GetPlayerFromCharacter(hit.Parent) --This will get the Player from the Player's Character
if Player and Player:FindFirstChild("leaderstats") and Player.leaderstats:FindFirstChild("Pumpkins") then --This will check to see if 'leaderstats, and 'Pumpkins' exist within the Player
Player.leaderstats.Pumpkins = Player.leaderstats.Pumpkins + 1 --This will increase Pumpkins by 1
script.Parent.Transparency = 1 --This will make the script's Parent's Transparent [If is a Part-Type object]
script.Parent.CanCollide = false --This will make the script's Parent Throughable [If is a Part-Type object]
wait(10)
script.Parent.Transparency = 0 --This will make the script's Parent non-Transparent again
script.Parent.CanCollide = true --This will make the script's Parent non-Throughable again
Debounce = true --This will enable the Player to use it again
end --This ends the code for the 'if' statement that checks to see if 'leaderstats' and 'Pumpkins' exist
end --This ends the code for the 'if' statement that checks to see if 'hit.Parent' exists, there are objects within it, checks to see if 'hit.Parent' is a Player, and checks to see if 'Debounce' is enabled so that it can fire
end --This ends the code for the function

script.Parent.Touched:connect(Pumpkin) --Now whenever the Part is touched, it'll fire an event [The 'Touched' event] that which will fire the function

Hope this helped!