version issue?

I have the following query running on two different servers. It works on
7.0.3 and gives the following error on 7.1beta4.

ERROR: Attribute 'last_name' not found

Your SQL statement:
SELECT first_name, last_name, middle_name, u.uid, end_year
FROM user_info u, auth a
WHERE u.uid = pri_key AND a.auth_table = 'user_info' AND live = 't'
AND site_id IN ('214') AND u.end_year > date_part('year', date 'today') - 2
UNION
SELECT first_name, last_name, middle_name, u.uid, end_year
FROM user_info u, current c
WHERE u.uid = c.uid
ORDER BY UPPER(last_name)

I'm figuring it is in the ORDER BY, but I'm not sure. Can anyone help me
out?

-Dan