Compared to an Oneiric installation lacking the problems, there was a file /etc/dpkg/dpkg.cfg.d/multiarch on the affected system, that contained one line: "foreign-architecture i386". After removing it, everything seems to be fine.
Compared to an Oneiric installation lacking the problems, there was a file /etc/dpkg/ dpkg.cfg. d/multiarch on the affected system, that contained one line: "foreign- architecture i386". After removing it, everything seems to be fine.