Thanks for the info.
So I suppose that I can't add that command into a sudoers file so that a password won't be asked (meaning the command will be executed properly) when Catorise Plus tries to refresh the menu.
Now a password is asked when executing the root command, and I prefer it that way.
If there is no easy way to achieve what I want I will just have to manually execute "sudo /opt/catorise/catorise" after making the changes in Catorise Plus GUI (not that often) and saving them (it seems to work this way, but it is not "ideal").