Does anyone have an Idea how to fix that?

Warhammer 40 000 Gladius Relics of War]$ ./start.sh
Running Warhammer 40,000: Gladius - Relics of War
/home/user/GOG Games/Warhammer 40 000 Gladius Relics of War/game/Binaries/Linux-x86_64/Gladius.bin: symbol lookup error: ./libgssapi_krb5.so.2: undefined symbol: krb5_ser_context_init, version krb5_3_MIT

The game does not ship with all required libraries, instead assumes your GNU/Linux distribution provides them in a compatible version. In your case not. I had the same problem with Fedora 32. The game developers fixed it with the latest patch, 1.6.0, by shipping the required compatible libraries with the game. Unfortunately the patch is not distributed on GOG, yet. I found out it is available on Slitherine website:
www.slitherine .com/game/warhammer-40000-gladius-relics-of-war/pc

I cannot post any links at this moment. You have to fix them on your own

Here are the commands:
# go to game directory (version 1.5.1 from GOG.com)
cd "${HOME}/GOG Games"
DIR="Warhammer 40 000 Gladius Relics of War"

# create backup folder
cp -a "${DIR}"{,".backup"}

# download patch; add "http://" below and remove the empty spaces
wget --timestamping 'ftp.matrixgames .com/pub/Warhammer40000GladiusRelicsOfWar/Gladius-RelicsOfWar-LinuxPatch-v1.06.00.00.zip'

# extract patch quietly, overwriting existing files
unzip -qo Gladius-RelicsOfWar-LinuxPatch-v1.06.00.00.zip -d "${DIR}/game/"

# make the executables executable (else "Permission denied" error message in terminal)
chmod +x "${DIR}/game/Binaries/Linux-x86_64/Gladius.bin"
chmod +x "${DIR}/game/Binaries/Linux-x86_64/ErrorReporter.bin"

# start game
"${DIR}/start.sh"

Wow that worked. Thank you very much!

Rename/remove/delete ~/GOG Games/Warhammer 40 000 Gladius Relics of War/game/Binaries/Linux-x86_64/libgssapi_krb5.so.2 file and run the game.


If that doesn’t help and the error like this:
libgssapi_krb5.so cannot open shared object file: No such file or directory

then install libgssapi-krb5-2 package using your distribution package manager (apt/pacman/zypper/dnf/yum etc):
- on Arch Linux, Manjaro use pamac for installing krb5 package or execute from terminal emulator:
sudo pacman -S krb5

On Debian (Ubuntu, Linux Mint etc) use Synaptic for installing libgssapi-krb5-2 package or from terminal:
sudo apt-get install libgssapi-krb5-2

If the problem is still present, then create a symbolic link from /usr/lib/x86_64-linux-gnu/libgssapi_krb5.so.2 to the ~/GOG Games/Warhammer 40 000 Gladius Relics of War/game/Binaries/Linux-x86_64/libgssapi_krb5.so.2.

You can also do it from the terminal:
ln -s /usr/lib/x86_64-linux-gnu/libgssapi_krb5.so.2 ~/GOG Games/Warhammer 40 000 Gladius Relics of War/game/Binaries/Linux-x86_64/libgssapi_krb5.so.2

You can also run from the terminal in game root directory:
export LD_LIBRARY_PATH="./game/Binaries/Linux-x86_64"
./start.sh

Or use steam-runtime.

That's all.

Game just crashed after playing about 1 hour. There was an Update but it didn't fix the problem to launch it out of the box. Maybe the update was just for Windows.

Also I noticed that the Linux version is not up to date. It is 1.05.01.00 .
For Windows there is 1.06.01.01 .

=(

Thanks that was even easier and worked too.