I had a bug causing the game to crash over and over, once it didn't I caught this error message :

[string "@AutoLooter/Libs/AceAddon-3.0-13/AceAddon-3.0.lua"]:66: in function <AutoLooter/Libs/AceAddon-3.0/AceAddon-3.0.lua:61>
[string "@AutoLooter/Libs/AceAddon-3.0-13/AceAddon-3.0.lua"]:494: in function `InitializeAddon'
[string "@AutoLooter/Libs/AceAddon-3.0-13/AceAddon-3.0.lua"]:619: in function <AutoLooter/Libs/AceAddon-3.0/AceAddon-3.0.lua:611>

Does this happens with only AutoLooter enabled?
Since the error is happening in a lib, it's probably AutoLooter being blamed for another addon problem just because its lib was loaded first.

Indeed it was with autoturnIn. I'm not familiar with wow addons bug stack soz, so could you tell me how I can provide further info?

Libraries usually have a protection to no load twice, that's why the wrong addon can appear in the stack. Anyway, you should report it to the autoturnIn Author.