AutoIncrement not working on this table only - Mailing list pgsql-novice

When I try to create a new row in this table and do not explicitly define a unique value for datadefindex I get the
followingerror message: 

 ERROR:  Cannot insert a duplicate key into unique index datadef_pkey

 Here is the INSERT statement that generated the error:

 tmdb=# insert into datadef (cfgmgmtid, datadefname, datadefformat,
datadefunits, datadefdescription)
 VALUES (2, 'TestValue', 'REAL', 'N/A', 'This is a test of placing a new
row without an explicit datadefindex');

 Here is the table definition:

 tmdb=# \d datadef
                                              Table "datadef"
        Column       |         Type          |
Modifiers


--------------------+-----------------------+---------------------------
--------
 -------------------------
  datadefindex       | integer               | not null default
nextval('datadef_
 datadefindex_seq'::text)
  cfgmgmtid          | integer               |
  datadefname        | character varying(80) | not null
  datadefformat      | character varying(80) | not null
  datadefunits       | character varying(80) | not null
  datadefdescription | text                  | not null
 Primary key: datadef_pkey
 Unique keys: datadefname_idx
 Triggers: RI_ConstraintTrigger_19507,
           RI_ConstraintTrigger_19509,
           RI_ConstraintTrigger_19511,
           RI_ConstraintTrigger_19513,
           RI_ConstraintTrigger_19515,
           RI_ConstraintTrigger_19659,
           RI_ConstraintTrigger_19661,
           RI_ConstraintTrigger_19663,
           RI_ConstraintTrigger_19665,
           RI_ConstraintTrigger_19667

 And finally here is the entry in the datadef_datadefindex_seq table:

 tmdb=# select * from datadef_datadefindex_seq;
       sequence_name       | last_value | increment_by | max_value  |
min_value |
  cache_value | log_cnt | is_cycled | is_called

--------------------------+------------+--------------+------------+----
-------+
 -------------+---------+-----------+-----------
  datadef_datadefindex_seq |          8 |            1 | 2147483647 |
1 |
            1 |      32 | f         | t
 (1 row)

 Notice that last_value = 8, owever the current number of rows in the
datadef table = 67.

 My current workaround is to do a MAX(datadefindex) on datadef, increment it by one and explicitly place that  value as
thedatradefindex for the new row, however I am worried about the database stability. 

 More information : If I DROP the database, recreate it, and enter
values into the table manually, the autoincrement works on this table. It seems that the problem arises after I reload
thedata into the table using the \i command on a file which was created using the pg_dump command. 

 I have recently upgraded from 7.2.1 to 7.2.3 using the RPM.

 Thanks in advance,

 ben