PG 9.3 complains about specified more than once ??? Those views worked in PG 9.1 + 9.2

Hi,

I ran into a major problem when I tried to import a backup from 9.1. into a 9.3 PG.

I just installed PG 9.3 on a new linux box.
Then I wanted to import a plaintext dump of a DB that was created by pg_dump of PG 9.1

There are a lot of views that have joins to a subquery in the from-clause.

something like

SELECT ... some columns ...
FROM
    maintable AS m
    JOIN someflag AS f ON m.flag_1_id = f.id
LEFT JOIN
(
    child_table     AS   c
    JOIN   someotherflag  AS  f   ON   c.flag_2_id = f.id
)   AS x  ON m.id = x.main_id

This works with PG 9.1 and PG 9.2 but PG 9.3 complains:

ERROR:  table name "f" specified more than once

Are there no separate namespaces for subqueries anymore in PG 9.3 ?

Do I have to change ALL those views in the old PG 9.1 server before I can import the backup into 9.3 or is there another way to work around this issue ?