Playonlinux is a GUI frontend for wine that
- stores/installs known working configurations for programs
- manage per-program wine installs/prefixes
official docs https://wiki.playonlinux.com/index.php/Main_Page
If you receive this error, and you *know* you have libgl installed (for your appropriate graphics driver), chances are that your graphics-driver was updated, and you have not yet rebooted. Giver a reboot and try again (or restart X).