Please note that the executable has been moved to a different folder. Manually select it in the new location under /bin in the game folder.
If you are using the non-Steam version of DCS World, you currently have to start Game Hub as an administrator as otherwise the headtracker.dll file that is located in %localappdata%\TobiiGameHub\app-2.3.1\HeadTracker.dll won't get automatically written to the game folder Eagledynamics\DCSWorld\bin where the executable is located.
Beta versions are not officially supported, but there is a workaround so you can make it work.
Just change the game folder name from DCS World Open Beta to DCS World.