You should not run "customize-cd-gui" as root in any way. You should start it as your normal user, it will prompt for sudo password (in console window) when it becomes necessary.
Try again and report if it works OK now.
You should not run "customize-cd-gui" as root in any way. You should start it as your normal user, it will prompt for sudo password (in console window) when it becomes necessary.
Try again and report if it works OK now.