Trying to index a Parent results in a nil value - lua

Question

Error:
16:16:03.496 - Workspace.Storeroom.Pile of Crates.Wood Crate.Script:17: attempt to index field 'Parent' (a nil value)
Script:
local db = true
local clickdetector = script.Parent:WaitForChild('ClickDetector')
clickdetector.MouseClick:Connect(function(plr)
local randomizer = math.random(1,6)
if randomizer == 1 or 2 or 3 then
script.Parent:Destroy()
local gift = game:GetService("ReplicatedStorage"):WaitForChild("Blue Keycard")
if db == true then
db = false
gift:Clone().Parent = plr.Backpack
wait(1)
db = true
end
end
if randomizer == 4 or 5 then
script.Parent:Destroy()
local gift = game:GetService("ReplicatedStorage"):WaitForChild("Red Keycard")
if db == true then
db = false
gift:Clone().Parent = plr.Backpack
wait(1)
db = true
end
end
if randomizer == 6 then
script.Parent:Destroy()
local gift = game:GetService("ReplicatedStorage"):WaitForChild("Green Keycard")
if db == true then
db = false
gift:Clone().Parent = plr.Backpack
wait(1)
db = true
end
end
end)

Answer 1

if randomizer == 1 or 2 or 3 then
if randomizer == 4 or 3 then
These lines won't work as you think it should. It doesn't check if randomizer value is in some set of predefined values. Expression randomizer == 1 or 2 or 3 evaluates (depending on randomizer exact value) either to true or to 2, which is interpreted as true in if/then construct.
If you really want to check the value against the list, you should do something like:
local set1 = {1=true, 2=true, 3=true}
local set2 = {4=true, 5=true}
-- somewhere much later
if set1[randomizer] then .. end
Start with fixing this issue.