I have exactly the same problem - also with german in feisty beta. County/Region & Language (kcmlocale) was at "C" for Country or Region and the Language was hence set to US-English (The desktop was translated to german, though -- only kcmlocale wasn't translated since it changes its language dynamically based on the language selection).
I have exactly the same problem - also with german in feisty beta. County/Region & Language (kcmlocale) was at "C" for Country or Region and the Language was hence set to US-English (The desktop was translated to german, though -- only kcmlocale wasn't translated since it changes its language dynamically based on the language selection).
Also attaching /var/log/ installer/ syslog ...