PostgreSQL 7.0 problem (may be bug?)

Hello

Consider two simple tables: AA, BB.

proba=# \d aa
Table "aa"
Attribute | Type | Modifier
-----------+---------+----------
id | bigint |
val | integer |

proba=# select * from aa;
id | val
----+-----
1 | 1
2 | 2
2 | 2
3 | 3
3 | 3
3 | 3
(6 rows)

proba=# \d bb
Table "bb"
Attribute | Type | Modifier
-----------+---------+----------
id | integer |
val | bigint |
occured | bigint |

proba=# insert into bb select id,val,count(val) from aa group by id,val;
pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!#

After that postmaster sould be rerun.

What is wrong ?
Would you mind to tell me how can I fix the situation.
Using PostgreSQL 7.0, Slackware 7.0.

I can give you the similar example on the same subject.
Again, two tables: CLICK, OTCHET_BROWS.
proba=# \d click
Table "click"
Attribute | Type | Modifier
------------+-----------+---------------------------------------------------------------
id_visitor | bigint |
ip | inet |
browser | integer |
referer | integer |
date | timestamp | not null default 'Fri Jul 20 21:36:05 2001 EEST'::"timestamp"

proba=# select id_visitor, browser, count(browser) from click group by id_visitor,browser;
id_visitor | browser | count
------------+---------+-------
1 | 1 | 20
1 | 2 | 17
1 | 3 | 2
3 | 2 | 1
(4 rows)

proba=# insert into otchet_brows select id_visitor, browser, count(browser) from click group by id_visitor,browser;
INSERT 0 6
proba=# select * from otchet_brows;
id_visitor | browser | value | date
------------+---------+-------+-------------------------------
1 | 1 | 2 | Mon Jul 23 17:04:53 2001 EEST
1 | 2 | 4 | Mon Jul 23 17:04:53 2001 EEST
1 | 1 | 18 | Mon Jul 23 17:04:53 2001 EEST
1 | 2 | 13 | Mon Jul 23 17:04:53 2001 EEST
1 | 3 | 2 | Mon Jul 23 17:04:53 2001 EEST
3 | 2 | 1 | Mon Jul 23 17:04:53 2001 EEST
(6 rows)

proba=#

What is the reason ?

Thanks in advance.

--
Vladimir Zolotych gsmith@eurocom.od.ua