Where is a mistake?

CREATE VIEW v1 AS SELECT n.net AS net,
n.sh_desc AS net_name,
count(s.ip) AS total_q
sum(s.bytes)/1024 AS Kb
FROM zgia_nets n,
squid_logs s
WHERE network_sub(s.ip,n.net)
AND
date_eq(dt::date,'24-05-2000')
AND
s.peer_stat != 'NONE'
GROUP BY net,net_name
ORDER BY Kb;

stats=> select t1.net,t1.net_name,t1.total_q,t1.total_q/sum(t2.total_q) from v1 t1,
v1 t2 group by 1,2,3;

pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
We have lost the connection to the backend, so further processing is
impossible. Terminating.

where is a mistake? or is it a bug?

I have PGSQL v 6.5.3.

--
Laa.