Unfortunately PaintDOTNet requires Microsoft's .NET Framework 4.7.2
That may have to be installed manually in the Wine prefix with the command prompt using Winetricks.
There may be a package for it in (Components) but if there isn't try running this command to install it with Winetricks... just make sure to add your username and prefix in the path...
Open Configure
Select the virtual drive (wine prefix) on the left column
Click Miscellaneous Tab
Click "Open a Shell"
Copy and paste this into the shell:
wget https://raw.githubusercontent.com/Winetricks/winetricks/master/src/winetricks
press Enter
Then copy and paste this:
chmod +x winetricks
Press Enter
Last copy & paste this command to install DotNet 472:
WINEPREFIX=/home/username/.PlayOnLinux/wineprefix/gamename ./winetricks -q dotnet472
Press Enter
That should do it... now download Paint DOT Net installer and run it from the Miscellaneous Tab by clicking "Run a exe file in this virtual drive"
Follow the installation steps...
Normally I would just do a manual installation with PlayOnLinux which includes running the installer, but you still might need DotNet 472 installed ahead of time.
Edited by booman