From an internet search, error 126 is likely missing libraries.  I don't know if that is a new machine, or perhaps some things were uninstalled, but my guess would be missing DirectX or missing Microsoft VC runtimes.  They are both available in the Maelstrom downloads.  DirectX needs 9.1c43, which can be obtained in the directx_Jun2010_redist, or dxwebsetup, which will take you to the Microsoft site for the update.  VC runtimes can also be obtained from Micrsoft's download site, where the 32 bit version you will need to runtimes compatible with Visual Studio 2017, or the 64 bit version, which is Visual Studio 2019.  Or, you can use the ones in the Maelstrom download, folders 2017VCRun, or 2019VCRun.

None of these requirements have recently changed, as it's been a couple years I've been using Visual Studio 2019 for the 64 bit, and the DirectX 9.1c43 was needed since day one.

I got the files in your email message.  Your ERAS directory contains an extra space and a 2 character at the end.  So your target should be this:

D:\Maelstrom\gentlemen-of-fortune-maelstrom-engine\DirectX9_64bit\Config.exe "D:\Maelstrom\Games\gentlemen-of-fortune-historical-eras-module-2 2"

Your system.log tells me this near the top, because it outputs the current directory Maelstrom is using:

Current dir: D:\Maelstrom\Games\gentlemen-of-fortune-historical-eras-module-2 2