sequence last_value

Hi

I really need help on this one. can any one please explain to me how
"SERIAL PRIMARY KEY "
works.
I keep getting the following err "Cannot insert a duplicate key into unique
index loc_pkey"

I have deleted this table and rebuild it, renamed it, deleted it and made a
new table with a new name and still get the above err's
(the table was called location)

wireman=# insert into loc values (1,1,'HELP');
ERROR:  Cannot insert a duplicate key into unique index loc_pkey

my table looks like this:

CREATE TABLE location (
    building_key INT2,
    floor INT2,
    ref VARCHAR(16),
    key_location SERIAL PRIMARY KEY
);

wireman=# select * from loc;
 building_key | floor | ref  | key_location
--------------+-------+------+--------------
            1 |     3 | 36   |            1
            1 |     3 | DA05 |            2
            1 |     3 | CN05 |            3
            1 |     3 | CB05 |            4
            1 |     3 | DG30 |            5
            1 |     3 | DF30 |            7
            1 |     3 | DR29 |            8
            1 |     3 | CO30 |            9
            1 |     3 | CM30 |           10
            1 |     3 | DF26 |           11
            1 |     3 | DD26 |           12
            1 |     3 | DF22 |           16
            1 |     3 | CR22 |           18
            1 |     3 | BV22 |           19
            1 |     3 | BT22 |           21
            1 |     3 | BV05 |           23
            1 |     3 | CT05 |           24
            1 |     3 | DC26 |           27
            1 |     3 | DR26 |           30
            1 |     3 | DM26 |           31
            1 |     3 | DG18 |           32
            1 |     3 | BV26 |           33
            1 |     3 | DM21 |           35
            1 |     3 | CO22 |           36
            1 |     3 | BT17 |           37
            1 |     3 | BU29 |           41
            1 |     3 | BT14 |           43
            1 |     3 | DR21 |           45
            1 |     3 | BT29 |           46
            1 |     3 | CP30 |           47
(30 rows)

or

wireman=# \d loc
                                     Table "loc"
  Attribute   |    Type     |                        Modifier

--------------+-------------+-----------------------------------------------
---------
 building_key | smallint    |
 floor        | smallint    |
 ref          | varchar(16) |
 key_location | integer     | not null default
nextval('loc_key_location_seq'::text)
Index: loc_pkey

I don't know if this matter but I got this,

wireman=# select * from loc_key_location_seq;
    sequence_name     | last_value | increment_by | max_value  | min_value |
cache_value | is_cycled | is_called
----------------------+------------+--------------+------------+-----------+
-------------+-----------+-----------
 loc_key_location_seq |          5 |            1 | 2147483647 |         1 |
1 | f         | t

now my other question is, where do I look to fix this problem?

i'm running PostgreSQL 7.0.3 on sparc-sun-solaris2.8, compiled by gcc 2.95.2

also see my previous post

thanx in advance.