9.0b1: "ERROR: btree index keys must be ordered by attribute"

Hi

I've just compiled the 9.0 beta1 source tarball and am testing my
custom application against it (which has been running on PostgreSQL
since 7.3 or so).

The below statement results in the following error message:

"ERROR: btree index keys must be ordered by attribute"

evidently in relation to the subselect. The statement works fine on
previous versions up to 8.4.3. I can provide more details later if
required:

SELECT o.object_id
FROM object o
INNER JOIN class c
ON (o.class_id = c.class_id)
INNER JOIN object_version ov
ON (o.object_id = ov.object_id)
INNER JOIN site
ON (o.site_id=site.site_id)
WHERE o.object_id = '3143'
AND ov.version = '0'
AND o.site_id = '2'
AND ov.object_status_id = (SELECT MAX(ov1.object_status_id)
FROM object_version ov1
WHERE o.object_id=ov1.object_id
AND ov1.version = ov.version
AND ov1.lang = ov.lang
)
AND ov.lang = 'en'

SELECT version():
PostgreSQL 9.0beta1 on i686-pc-linux-gnu, compiled by GCC gcc (Ubuntu
4.3.2-1ubuntu12) 4.3.2, 32-bit
Ubuntu 8.10 running on a "VIA C7-M" Processor (netbook).

Regards

Ian Barwick