In Included archive there is test environment worked with fasmg version g.hw7gf and earlier versions.
(I remove from test environment mostly everithing dosn`t relative to problem)
From some version (minimum from g.hxmfv (september)) there is error.
I can`t detect where exactly this error.

To initialize package for unziped folder - used init.bat in it.(it makes FASMG.INI with correct paths)
open fasmw.exe inside package, than open one of examples, than compile it with menu run->fasmg:mkbin (this menu added - only one difference from oficial version)
with replacing fasmg.exe in package with new version than you will get error when you will make same algorithm as described above.

it looks like fasmg incorrect working with paths with .. inside or something like that.

Maybe fasmg syntax slightly upgraded from summer? And I missed that?

with last fasm g version

Code:

start: 25.12.2017 12:23:08,52 source file: C:\Users\NikiforovPM\Desktop\Ќ®ў п Ї ЇЄ \EXAMPLES_G\x86\Win\x86\fromMASM32\AniWindow\withDIALOG.asm flat assembler  version g.hxmfv C:\Users\NikiforovPM\Desktop\Новая папка\EXAMPLES_G\x86\Win\x86\fromMASM32\AniWindow\withDIALOG.asm [3]:         format PE GUI 4.0 Processed: format PE GUI 4.0 Error: invalid argument. finish: 25.12.2017 12:23:08,64

with fasmg version g.hw7gf

Code:

start: 25.12.2017 12:46:16,16 source file: C:\Users\NikiforovPM\Desktop\Ќ®ў п Ї ЇЄ \EXAMPLES_G\x86\Win\x86\fromMASM32\AniWindow\withDIALOG.asm flat assembler  version g.hw7gf 4 passes, 0.3 seconds, 3584 bytes. finish: 25.12.2017 12:46:16,54

The FORMAT is now a built-in instruction in fasmg (to allow fasm-compatible FORMAT BINARY AS 'EXT' setting), so if you re-define it as a macro, it cannot be forward referenced. When you use FORMAT before the macro gets defined, the built-in instruction is used instead.

However, the built-in FORMAT has been made to work like the END directive, so you can define sub-macros in its namespace. So a macro named FORMAT?.PE can be forward-referenced, as the built-in FORMAT directive looks for the instructions/macros in the FORMAT? namespace and calls them.

You can see this new method used in the updated headers for Win32/Win64.