GFx SDK 3.3 is required for the flash files (also known as .gfx and .swf).
Download: (Updated 4/26/2020)
https://mega.nz/file/Fl0DVAJC#SZu7hgWBXpZ5UZgxvEKwBgHVlmhd2hruxLv-v9CgR7s
How to install:
Extract the folder into "DBOGLOBAL\DboClient\Lib\NtlFlasher". Then it should look like this