This error indicates, that there are nothing to connect to. You can ignore it, just run DCS and hop into hornet. If you still getting this error, You might have DCS-Bios installed incorrectly. Reposting from reddit detailed intruction:
Install https://support.logitech.com/software/lgs
Copy contents of http://gaming.logitech.com/sdk/LCDSDK_8.57.148.zip into C:\Program Files\Logitech Gaming Software\LCDSDK_8.57.148
From https://github.com/dcs-bios/dcs-bios copy folder "Scripts" and paste it to C:\Users\XXX\Saved Games\DCS.openbeta\Scripts
Then, into "export.lua" in C:\Users\XXX\Saved Games\DCS.openbeta\Scripts (you can create it, if it isn't exist) paste line dofile(lfs.writedir()..[[scripts\DCS-BIOS\BIOS.lua]]
Next: copy contents DCS-BIOS v1.0.zip into C:\Users\XXX\Saved Games\DCS.openbeta\Scripts (merge these folders). This is Hornet-specific extension for dcs-bios.
Install latest version of python https://www.python.org/downloads/ (not required if using EXE)
Finally, download my repository (once again), unpack anywhere, I've added run.bat (or ./dist/specelUFC.exe) so you can run it simply. You should see command console window with connection error every two seconds, or with Connected message if your DCS is up and running