Glad you managed to get it working!
Hope you will be able to get it running on Linux too.
You can see the install instructions for Linux for some possible clues:
FPV Freerider is distributed as a Linux executable, not a package. Create a "bin" folder in your home directory (this isn't necessary but traditionally binary executables go in the bin folder). Unzip the FPVFreerider_linux.zip file into that directory. Open FPVFreerider. Right click on the appropriate executable for your system (32 or 64 bit), and select 'Properties'. Click the 'Permissions' tab. At the bottom of that tab check: 'Execute: Allow executing file as a program'. Now when you want to play, just double click that icon.
(When using a Taranis on Linux, the joystick driver by default adds some dead zone to the sticks around their center position. Running "$ jscal -c /dev/input/js0" and recalibrating the Taranis within Linux should remove the dead zone. Source: Joystick Emulation - Manual for OpenTX ).
Tip: If you are not able to run the sim on your Linux machine you might have to force Open GL:
user@computer:~$ ./FPVFreerider.x86_64 -force-opengl