Statistics Collector not collecting server activities

Hi,

Even though I've enabled statistics collector in our server, it is not
collecting statistics, and because of this autovacuum is also not running as
expected.

PostgreSQL version 8.2

Parameters enabled related to this are:

# - Query/Index Statistics Collector -

#stats_command_string = on

#update_process_title = on

#stats_start_collector = on

#stats_block_level = off

#stats_row_level = off

stats_block_level = on

stats_row_level = on

#stats_reset_on_server_start = off

# - Statistics Monitoring -

#log_parser_stats = off

#log_planner_stats = off

#log_executor_stats = off

#log_statement_stats = off

I'm always getting zero value for all the tables.

select pg_stat_get_tuples_inserted((select oid from pg_class where relname =
'mytable'));

select pg_stat_get_tuples_updated((select oid from pg_class where relname =
'mytable'));

select pg_stat_get_tuples_deleted((select oid from pg_class where relname =
'mytable'));