Been getting these recently, not sure when it started, maybe weekly reset on the 9th?

19x tdBattlePetScript/Rematch/UI.lua:53: attempt to call method 'GetMenu' (a nil value)
[string "@tdBattlePetScript/Rematch/UI.lua"]:53: in function <tdBattlePetScript/Rematch/UI.lua:52>
[string "=[C]"]: ?
[string "@Ace3/AceAddon-3.0-13/AceAddon-3.0.lua"]:66: in function <Ace3/AceAddon-3.0/AceAddon-3.0.lua:61>
[string "@Ace3/AceAddon-3.0-13/AceAddon-3.0.lua"]:523: in function <Ace3/AceAddon-3.0/AceAddon-3.0.lua:516>
[string "=(tail call)"]: ?
[string "@tdBattlePetScript/Core/Manager/PluginManager.lua"]:149: in function `LoadPlugins'
[string "@tdBattlePetScript/Core/Manager/PluginManager.lua"]:33: in function <...Ons/tdBattlePetScript/Core/Manager/PluginManager.lua:32>

I have, I'm using Rematch 5_0_0_beta_10, I'm not sure I understand what they're talking about in the post you linked. Is the error related to storing scripts? isn't that the whole point of pet battle scripts?

This addon currently does not support Rematch 5, only Rematch 4.

Did you update Rematch to version 5? If yes, there is no support yet, see #45.