Please include as much of the following information as possible to help me fix the bug:

When I click on an item from the bag I get this error message

Loaded Addons

Auctionator
BtwLoadouts
Buggrabber
Bugsack
DeModal
Details!
Immersion
Krowi's achievement Filter
Leatrix Maps
Leatrix Plus
LFGSpamFilter
LS: Toasts
OmniCC
Simulationcraft
TL:DR Missions
WeakAuras

Back Trace (LUA Error Output)

1x [ADDON_ACTION_FORBIDDEN] AddOn 'Auctionator' hat versucht die geschützte Funktion 'UNKNOWN()' aufzurufen.
[string "@Interface/AddOns/!BugGrabber/BugGrabber.lua"]:480: in function <Interface/AddOns/!BugGrabber/BugGrabber.lua:480>
[string "=[C]"]: ?
[string "=[C]"]: in function UseContainerItem' [string "@Interface/FrameXML/ContainerFrame.lua"]:1384: in function <Interface/FrameXML/ContainerFrame.lua:1294> [string "=[C]"]: in function ContainerFrameItemButton_OnClick'
[string "@Interface/FrameXML/ContainerFrame.lua"]:1435: in function <Interface/FrameXML/ContainerFrame.lua:1423>

WIP for fixing this.

In the interim to work around the bug you can use the chat command /reload to stop it (at least until the next time you close the AH)

Fixed in the latest alpha
Auctionator-10.0.3-10-g6dec85e.zip