Can you give me the complete path to your maps, like "/home/....."
Tell me also the complete path to your dedicated_cfg file.
And the one of your matchsettings file.
Your dedicated server didn't find your matchsetting file.
I am using Debian too so i need more information to help you
For example :
I have this in my .sh file (to launch the server) :
My maps are there : /home/<user>/TM2/UserData/Maps/Challenges/<server_name>cd /home/<user>/TM2
./ManiaPlanetServer /title=TMStadium@nadeo /game_settings=MatchSettings/<server_name>.txt /dedicated_cfg=dedicated_cfg.<server_name>.txt
and my matchsettings here : /home/<user>/UserData/Maps/MatchSettings/
Thanks