[#3058] - JasperServer does not execute a query that iReport does.

Software
iReport 4.7.1
JasperServer 4.7.0
DB (Postgresql) 8.4

On iReport when executing a query like

(select * from table1)
union
(select * from table1)

It runs as expected however on JasperServer it fails with error:

"An error has occurred. Please contact your system administrator. (6632)"

This query works fine on both iReport and JasperServer

select *
from (
(select * from table1)
union
(select * from table1)
) t

Regards.