Help with GetMouse Method?

For some rason this works well on solo but on a server I keep getting a error saying:

Workspace.Model.Screen.Game.Game.Controls:13: attempt to index local 'PlayersMouse' (a nil value)

Oh and the script is just a regular one not local.

why did I get this error and how do I fix it?

local BlueBar = script.Parent.GAME.BluPdl
local RedBar = script.Parent.GAME.RedPdl
local BlueSeat = script.Parent.Parent.Parent.Parent.BlueSeat
local RedSeat = script.Parent.Parent.Parent.Parent.RedSeat
----------------------BlueSeat----------------------------
BlueSeat.ChildAdded:connect(function(Part)--Checks if a Player has been steated
    if Part.Name == "PlatformMotor6D" and Part.Part1.Name =="Torso" then
    ---------------------Vairbles-------------------------
    local Character = Part.Part1.Parent
    local Player = game.Players:GetPlayerFromCharacter(Character)
    local PlayersMouse = Player:GetMouse()
    ------------------------------------------------------
    BlueSeatConnection = PlayersMouse.KeyDown:connect(function(Key)
            if Key == "w" then
                if BlueBar.Position.Y.Offset > 0 then -- Rise Up if pressed w
                    BlueBar.Position = UDim2.new(0, 0, 0, (BlueBar.Position.Y.Offset - 20))
                end
            elseif Key == "s" then
                if BlueBar.Position.Y.Offset < 400 then
                    BlueBar.Position = UDim2.new(0, 0, 0, (BlueBar.Position.Y.Offset + 20))
                end
                BlueSeat.ChildRemoved:connect(function(Part)
                    if Part.Name == "PlatformMotor6D" and Part.Part1.Name =="Torso" then
                        BlueSeatConnection:disconnect()
                    end
                end)
            end
        end)
    end
end)
----------------------RedSeat------------------------------
RedSeat.ChildAdded:connect(function(Part)--Checks if a Player has been steated
    if Part.Name == "PlatformMotor6D" and Part.Part1.Name =="Torso" then
    ---------------------Vairbles-------------------------
    local Character = Part.Part1.Parent
    local Player = game.Players:GetPlayerFromCharacter(Character)
    local PlayersMouse = Player:GetMouse()
    ------------------------------------------------------
    RedSeatConnection = PlayersMouse.KeyDown:connect(function(Key)
            if Key == "w" then
                if RedBar.Position.Y.Offset > 0 then
                    RedBar.Position = UDim2.new(0, 560, 0, (RedBar.Position.Y.Offset - 20))
                end
            elseif Key == "s" then--Rise down if s is pressed
                if RedBar.Position.Y.Offset < 400 then
                    RedBar.Position = UDim2.new(0, 560, 0, (RedBar.Position.Y.Offset + 20))
                end
                RedSeat.ChildRemoved:connect(function(Part)
                    if Part.Name == "PlatformMotor6D" and Part.Part1.Name =="Torso" then
                        RedSeatConnection:disconnect()
                    end
                    end)
            end
        end)
    end
end)