db_query problem

I'm having a problem with an SQL query that works with mysql_query but not with db_query. I'm running MySQL 5.0. Here is a table I added:

CREATE TABLE `user_profile` (
`uid` int(10) unsigned NOT NULL default '0',
`company_name` varchar(60) default '',
`first_name` varchar(60) default '',
`last_name` varchar(60) default '',
`address` varchar(255) default '',
`city` varchar(60) default '',
`state` varchar(60) default '',
`zip_code` varchar(60) default '',
`practice_type` varchar(60) default '',
`phone` varchar(60) default '',
`fax` varchar(60) default '',
`enrollment_status` varchar(60) default '',
`graduation_year` int(11) unsigned default '0',
PRIMARY KEY (`uid`)
)

I get one row as expected with the following code used with mysql_query:
SELECT p.*, r.rid, u.name as user_name, u.created FROM users u INNER JOIN user_profile p ON u.uid = p.uid INNER JOIN users_roles r ON p.uid = r.uid WHERE (r.rid = 4 || r.rid = 5) AND (p.first_name LIKE "%blah%" OR p.last_name LIKE "%blah%")

But the following returns zero rows with db_query:
SELECT p.*, r.rid, u.name as user_name, u.created FROM {users} u INNER JOIN {user_profile} p ON u.uid = p.uid INNER JOIN {users_roles} r ON p.uid = r.uid WHERE (r.rid = 4 || r.rid = 5) AND (p.first_name LIKE "%blah%" OR p.last_name LIKE "%blah%")

I have to admit, I'm not a database expert, so if I'm doing something stupid, let me know. :)

Thanks,
Dave