Hi, I am having the same problem (amd64, testing, current version of all apt and - related packages). Weird enough, if the update fails and I run it again, it succeeds. A tar-gzipped copy of /var/lib/apt/lists directly after the errornous update ended is currently uploading to http://www.ralfj.de/upload/debian/ (should be finished in 20 to 30 minutes). Kind regards, Ralf