I found even if you install it from the maemo.org site Xournal will not start after you have started it and then close it by clicking the 'x' in the upper right hand corner. You MUST Quit Xournal from it's menu, if not it will still be running in the background. The only way to quit it then will be to run 'Top' in a terminal to find the PID number for Xournal and run 'Kill' the PID number for Xournal OR reboot.