*always make a backup of your original config files! cp /etc/proftpd.conf /etc/proftpd.conf.orig!!!*
delete or comment out '#' the entire <anonymous> section.
and i noticed you also seem to have a duplicate section:
# To cause every FTP user to be "jailed" (chrooted) into their home
# directory, uncomment this line.
#DefaultRoot ~
# Normally, we want files to be overwriteable.
AllowOverwrite on
# To cause every FTP user to be "jailed" (chrooted) into their home
# directory, uncomment this line.
#DefaultRoot ~
# Normally, we want files to be overwriteable.
AllowOverwrite on
remove one of the duplicates, and then, uncomment the defaultroot~ command.
give that a shot. let me know if it works for you.