It may be because you don't have a deb-src entry for "multisystem". Try commenting out that line in your sources.list. If that doesn't work then keep testing by removing extras.ubuntu.com and archive.canonical.com to see if that helps.
It may be because you don't have a deb-src entry for "multisystem". Try commenting out that line in your sources.list. If that doesn't work then keep testing by removing extras.ubuntu.com and archive. canonical. com to see if that helps.