The GtkDialog warning is normal & nothing to be concerned about. "WARNING: VIDEOS_DIRNAME is blank!" suggests the prefix wasn't initialised properly though.

I suspect you're missing some dependencies, but it could just be Zorin being a bit weird as I've had others report mysterious issues on Zorin before as well.

What happens if you try running the start script like this:

WINEDEBUG="" ./start.sh play

?

Thank you adamhm or your quick reply.

Not so bad the latest version of Zorin 15.2!
I did a test with Mint 19.3, it doesn't work much better and with more error messages (icootils not installed and Wine cannot find the ncurses library (libncurses.so.5)?).

But for my installation on Zorin by typing your order:
max@max-asrock:~/Games/Fallout New Vegas$ WINEDEBUG = "" ./start.sh play
WINEDEBUG : commande introuvable
max@max-asrock:~/Games/Fallout New Vegas$

While typing ./start.sh:
max@max-asrock:~/Games/Fallout New Vegas$ ./start.sh
Current desktop resolution: 2560x1440
Detected 8 display output(s). Connected outputs:
DVI-D-0: 2560x1440 (primary)
Gamma (R/G/B) = 1.000 / 1.000 / 1.000
Wine version: wine-4.0 (Staging)
Prefix is 32-bit
WARNING: VIDEOS_DIRNAME is blank!
Userdata directory: /home/max/.local/share/falloutnv
Gtk-Message: 21:10:16.603: GtkDialog mapped without a transient parent. This is discouraged.

But the graphic window of the menu appears!
I start the game with "Play"...

Running: FalloutNVLauncher.exe
Working directory: /home/max/Games/Fallout New Vegas/prefix/drive_c/Fallout New Vegas
Not forcing virtual desktop
wine: cannot find L"C:\\windows\\system32\\winemenubuilder.exe"
-> Red 1.000, Green 1.000, Blue 1.000
<- Red 1.000, Green 1.000, Blue 1.000
max@max-asrock:~/Games/Fallout New Vegas$

The game seems to work well with the graphics restrictions you specify in falloutnv_rel_notes.txt.
I do not have this problem of image quality with the Lutris version, on the other hand I do not have an intro and no background music? The picture is better.., but not its wav, a real dilemma!

It sounds a lot like you're missing some dependencies. On Mint 19.x you can simply install my common dependencies meta-package to install them.

That didn't work because you've added spaces either side of =. It needs to be exactly like this:

WINEDEBUG="" ./start.sh play

The way you've done it the shell will interpret WINEDEBUG as a command rather than an environment variable to set.

What an ass! Betrayed by the copy paste Google trad!
All my excuses.

Here with the right command:

max@max-asrock:~/Games/Fallout New Vegas$ WINEDEBUG="" ./start.sh play
Current desktop resolution: 2560x1440
Detected 8 display output(s). Connected outputs:
DVI-D-0: 2560x1440 (primary)
Gamma (R/G/B) = 1.000 / 1.000 / 1.000
Wine version: wine-4.0 (Staging)
Prefix is 32-bit
WARNING: VIDEOS_DIRNAME is blank!
Userdata directory: /home/max/.local/share/falloutnv
Running: FalloutNVLauncher.exe
Working directory: /home/max/Games/Fallout New Vegas/prefix/drive_c/Fallout New Vegas
Not forcing virtual desktop
000b:fixme:winediag:start_process Wine Staging 4.0 is a testing version containing experimental patches.
000b:fixme:winediag:start_process Please mention your exact version when filing bug reports on winehq.org.
wine: cannot find L"C:\\windows\\system32\\winemenubuilder.exe"
000b:err:wineboot:ProcessRunKeys Error running cmd L"C:\\windows\\system32\\winemenubuilder.exe -a -r" (2)
0009:fixme:msvcp:_Locinfo__Locinfo_ctor_cat_cstr (0x33f0ac 1 C) semi-stub
0009:fixme:msvcp:_Locinfo__Locinfo_ctor_cat_cstr (0x33f21c 1 C) semi-stub
0009:err:winediag:wined3d_dll_init Setting multithreaded command stream to 0x1.
0009:fixme:msvcrt:__clean_type_info_names_internal (0x10066a1c) stub
0009:fixme:msvcrt:__clean_type_info_names_internal (0x9c29a4) stub
-> Red 1.000, Green 1.000, Blue 1.000
<- Red 1.000, Green 1.000, Blue 1.000
max@max-asrock:~/Games/Fallout New Vegas$

For Mint 19, thank you, I downloaded the pack, I will try again as soon as possible

yuppy