Insert problem

I have a table  where some of the entries of should have
been posted to the wrong cusid and item#:

cusid |  item# |
1747  |  149   | 9251 : Jonathon Krinke .......
1747  |  150   | 10071 : Lindsey Steele ........
1747  |  151   | 10187 : Lindsay Stapley .......
1747  |  152   | 10188 : Amanda Goucher ........
1888  |    0   | 10071 : PROM 75P1206 mi.........

corrected:

1747 |  148 | 9250 : Jonathon Krinke ........
1747 |  149 | 9251 : Jonathon Krinke .......
1888 |    0 | 10071 : PROM 75P1206 mi......
1888 |    1 | 10071 : Lindsey Steele
1888 |    2 | 10187 : Lindsay Stapley
1888 |    3 | 10188 : Amanda Goucher

my correction script:

The script worked fine untill I tried in on the following entries:

1841 |    2 | 9228 : Caty Case : SO:Bra:.....
1841 |    3 | 9621 : Kelsie Greenlee : PROM.....

2072 |    3 | null : Cookie Jared Cook :..........
2072 |    4 | null : Cookie Jared Cook :........
2072 |    5 | null : Cookie Jared Cook :........

insert into schItem (scid,  value, iflag, outalts, sidate, istid)             select 2072,  i.value, i.iflag,
i.outalts,i.sidate, i.istid      from schItem i, schItem s        where i.scid=1841 and i.item >= 3              and
s.scid= 2072                    group by i.value, 
 
i.iflag, i.outalts, i.sidate, i.istid, s.scid

ERROR:  duplicate key violates unique constraint "schitem_pkey"

It seems I have something wrong with the select portion of the script
but I can figure it out.
Any idea??
thanks


ps
table defination


create sequence schItem_item_seq
create table schItem (scid                 int NOT NULL references schedule ON DELETE CASCADE,  item
intNOT NULL default nextval('schItem_item_seq'),  value                text,  iflag                int,  outalts
     int,  sidate               date,  istid                int references stock,  primary key (scid, item))
 



-- 
Arthur R. Van Hook

hook@lota.us
avanhook3@comcast.net

(816) 578-4704 - Home
(816) 629-0071 Cell


-- 
Arthur R. Van Hook

hook@lota.us
avanhook3@comcast.net

(816) 578-4704 - Home
(816) 629-0071 Cell