These are known error messages. A little searching would have netted this:
http://wiki.contribs.org/Updating_to_SME_7.2#10fix_privilege_tables_in_message_logWhich states this:
10fix_privilege_tables in message log
These messages are generated by
/usr/share/mysql/mysql_fix_privilege_tables.sql. The script itself says:
You can safely ignore all 'Duplicate column' and 'Unknown column' errors
because these just mean that your tables are already up to date.
This script is safe to run even if your tables are already up to date!