If some of your Knoppix apps are not behaving well, they may need an update.

Usually a re-load of Synaptic will present some new opportunities, but if
that fails, there's one other spot in Knoppix you should look at before you
start composing a forum thread. Look at MainMenu>Knoppix>install components.

You might be surprised to learn their are five updates there currently:
These are for audacity, flash, mplayer, openshot and ttf-mscorefonts.