Hey guyz!!
Sorry for late response.

I've fixed the exceptions.
System.ArgumentOutOfRangeException: Non-negative number required.
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Atlantis introduced second relic bonus and var2(don't know what it is) to the player save files.
So the file format changed. I've updated the parsing code.
Error loading resources System.IO.InvalidDataException: TEX magic is invalid.
Some how latest updates bugged the Eitr charm icon/image. I can't see eitr charm in version 2.7 properly it's broken.
I've silenced the exception in the blacksmith tool. Till they fix the icon it'll show as orange square with black question mark in it.
Get the TQBlacksmith v1.4 from main post.
Make sure you backup the save files before trying the latest tool version 1.4.
I don't have Atlantis DLC but I've tested it on 'TitanQuest v2.7' which is the latest.
I think it'll work on Atlantis DLC as well. If Atlantis has introduced new weapons and other items, then they won't show in the tool.

Let me know if any issues.