Estrange error

I'm having the following error:
SELECT codigo, estado FROM entrega WHERE servico='1' GROUP BY estado ORDER
BY estado

Warning: PostgresSQL query failed: ERROR: Illegal use of aggregates or non-
group column in target list in /home/httpd/html/websites/wrodonto.com.
br/html/carrinho.php3 on line 487

The srange thing is that this error only occur in one of the servers.

Mateus T Machado
E-mail: mtarcinalli@ig.com.br
ICQ: 40075236

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