Script:
script.Parent.MouseButton1Click:connect(function()
script.Parent.BackgroundColor3 = Color3.new(255,0,0)
key = game.ServerStorage.RoomKeys.Room1
clone = key:Clone()
compuser = game.Workspace.Comp1Plr
plr = game.Players:FindFirstChild(compuser.Value)
print("Found Computer User.") --It does print that
clone.Parent = plr.Backpack
end)
OutPut: Workspace.Comp1.Screen.SurfaceGui.AvailableRooms.Room1.Scri:8: attempt to index global 'plr' (a nil value)

3 comments
It most likely is because you did something wrong, and that is not an actual player?
I agree with Tempestatem. Your output means that 'plr' is nil.
Thanks guys, the player's name was not recorded in the string value thats why, I fixed it now. Thanks!