I already installed it. But the solarus editor is unusable. I don't know why.
Please open the terminal and give the output of the following two commands:
cat /etc/*-release
This command will give us more information about exactly what distro you are running, and what version. Then perhaps someone can reproduce the problem.
solarus-quest-editor
By running the quest editor from the command line instead of the applications menu, we will be able to see exactly why it fails by looking at the error output.