Gnuplot errors or warnings

Dear FLUKA and Flair experts,
I am new to FLUKA and Flair.I successfully installed FLUKA and Flair on Windows 10 (Ubuntu18.04 Virtual Machine).I was trying to run the “FLUKA tutorial” from the official Flair site .I got to the point 5 (Geometry Plotting) and then I got a figure with an error or warning message.

After clicking the output button,I got the following messgaes:

I seem to be able to ignore it and run FLUKA successfully. Does it matters? Will it cause any problems in the future?

Dear Shiqiang Pang,

the error messages are related to Gnuplot and the GTK window manager in Ubuntu.
If your plots created successfully, you can ignore this error message.

Also you could try to install the packages, which are possibly missing with the command:

sudo apt install libcanberra-gtk-module libcanberra-gtk3-module