I got the error 121 times, when playing roughly an hour:

121x D4KiR MoveAndImprove/core.lua:5521: attempt to call global 'GetContainerItemLink' (a nil value)
[string "@D4KiR MoveAndImprove/core.lua"]:5521: in function <D4KiR MoveAndImprove/core.lua:5513>
[string "=[C]"]: in function ContainerFrame_Update' [string "@FrameXML/ContainerFrame_Shared.lua"]:292: in function ContainerFrame_OnShow'
[string "*ContainerFrame.xml:492_OnShow"]:1: in function <[string "*ContainerFrame.xml:492_OnShow"]:1>
[string "=[C]"]: in function Show' [string "@FrameXML/ContainerFrame_Shared.lua"]:982: in function ContainerFrame_GenerateFrame'
[string "@FrameXML/ContainerFrame_Shared.lua"]:128: in function ToggleBag' [string "@FrameXML/ContainerFrame_Shared.lua"]:154: in function ToggleBackpack'
[string "@FrameXML/MainMenuBarBagButtons.lua"]:54: in function `BackpackButton_OnClick'
[string "*MainMenuBarBagButtons.xml:119_OnClick"]:4: in function <[string "*MainMenuBarBagButtons.xml:119_OnClick"]:1>

Locals:
self = ContainerFrame1 {
0 =
PortraitButton = ContainerFrame1PortraitButton {
}

this addon is outdated, it will be replaced when the two others are done

moveany, improveany