Most likely because:
-rw-r----- 1 root root 42547 2011-02-10 20:30 /var/log/dist-upgrade/apt.log
This log is not readable by non-root users.
Most likely because:
-rw-r----- 1 root root 42547 2011-02-10 20:30 /var/log/ dist-upgrade/ apt.log
This log is not readable by non-root users.