Why am I getting this error when I try to rename a value?

Im trying to store the name of a part in a string variable. but I keep getting this error: Players.Paczki_TCBC.PlayerScripts.LocalScript:35: invalid argument #3 (string expected, got Instance)

here's the part of my script that is broke:

UIS.InputEnded:Connect(function(input)
    if input.KeyCode == Enum.KeyCode[pickupkey] then
        if mouse.Target then
            if mouse.Target:FindFirstChild("Pickable") then
                local item = mouse.Target
                if item then
                    local distanceFromItem = player:DistanceFromCharacter(item.Position)
                    if distanceFromItem < 7 then
                        -- we fill this in loadstring
                        print("poopy")
                        game.ReplicatedStorage.Items.Value = item -- THIS IS THE TROUBLSOME LINE
                        PickupItem:FireServer(item)
                    end
                end
            end
        end
    end
end)