1x ...ker\libs\CustomTutorials-2.1\CustomTutorials-2.1-10.lua:150: attempt to call method 'SetBackdrop' (a nil value)
[string "@PetTracker\libs\CustomTutorials-2.1\CustomTutorials-2.1-10.lua"]:150: in function <...ker\libs\CustomTutorials-2.1\CustomTutorials-2.1.lua:125>
[string "@PetTracker\libs\CustomTutorials-2.1\CustomTutorials-2.1-10.lua"]:181: in function RegisterTutorials' [string "@PetTracker\addons\config\tutorials.lua"]:43: in function Load'
[string "@PetTracker\addons\config\tutorials.lua"]:27: in function ?' [string "@PetTracker\libs\WildAddon-1.0\WildAddon-1.0-1.lua"]:20: in function <...dOns\PetTracker\libs\WildAddon-1.0\WildAddon-1.0.lua:18> [string "@PetTracker\libs\WildAddon-1.0\WildAddon-1.0-1.lua"]:56: in function <...dOns\PetTracker\libs\WildAddon-1.0\WildAddon-1.0.lua:53> [string "=[C]"]: ? [string "@DataStore\libs\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:29: in function <...ore\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:25> [string "@DataStore\libs\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:64: in function Fire'
[string "@datastore\libs\AceEvent-3.0\AceEvent-3.0-4.lua"]:120: in function <DataStore\libs\AceEvent-3.0\AceEvent-3.0.lua:119>
[string "=[C]"]: in function LoadAddOn' [string "@PetTracker\addons\main\main.lua"]:46: in function ?'
[string "@PetTracker\libs\WildAddon-1.0\WildAddon-1.0-1.lua"]:20: in function <...dOns\PetTracker\libs\WildAddon-1.0\WildAddon-1.0.lua:18>
[string "@PetTracker\libs\WildAddon-1.0\WildAddon-1.0-1.lua"]:56: in function <...dOns\PetTracker\libs\WildAddon-1.0\WildAddon-1.0.lua:53>
[string "=[C]"]: ?
[string "@datastore\libs\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:29: in function <...ore\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:25>
[string "@datastore\libs\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:64: in function Fire' [string "@DataStore\libs\AceEvent-3.0\AceEvent-3.0-4.lua"]:120: in function <DataStore\libs\AceEvent-3.0\AceEvent-3.0.lua:119> [string "=[C]"]: in function LoadAddOn'
[string "@FrameXML\UIParent.lua"]:495: in function UIParentLoadAddOn' [string "@FrameXML\UIParent.lua"]:618: in function TimeManager_LoadUI'
[string "@FrameXML\UIParent.lua"]:1373: in function <FrameXML\UIParent.lua:1258>

This is after applying the patch/changes as recommended in this thread:
#213 (comment)

I might have solved that:

https://github.com/spiralofhope/CustomTutorials-2.1/commit/d73286564635cc5f5dfa6106eb3e45666ae3e756

Does that change work for you?

I can't test this problem because I don't know how to reproduce it.