Yes, it was not about icons (where full path is not only not needed, but must not be set, to my experience).

But I have to apologize, Estel.
Of course a sudo in front of command does not require full path!

But I had similar once and thought it was that (not having root rights); and it was late...

As I just greyed out my nonsense in former post, it was not fully nonsense ;j My script is in totally different location!

karlitos
can you run
sudo bnf
from terminal as user (not as root)?
Please open a new x-term and directly type
sudo bnf

If that starts the window or black screen, then give us output of
lsmod | grep bq27