hi to all!

This is query I used before we moved to mysql4 based dedicated server:

SELECT ".$tn.".reg_id, b.*, sh.*
FROM ".$tn.", bill_info as b
LEFT JOIN shipp_info as sh ON (b.bill_id=sh.bill_id)
WHERE b.reg_id = ".$tn.".reg_id
AND b.table_name = '".$tn."'
AND ".$tn.".registration_status = '".$_SESSION['order_status']."'
ORDER BY ".$tn.".reg_id DESC

($tn is name for selected table)

Now, after I moved to mysql5 based server I'm getting error:
ERROR: Unknown column 'b.bill_id' in on clause
?!?!?

CREATE TABLE `bill_info` (
`bill_id` int(10) unsigned NOT NULL auto_increment,
`ref_no` varchar(14) default NULL,
`reg_id` int(5) unsigned default NULL,
`cc_id` int(5) unsigned default NULL,
`table_name` varchar(50) NOT NULL default '',
`bill_name` varchar(100) NOT NULL default '',
`bill_address_1` varchar(100) NOT NULL default '',
`bill_address_2` varchar(50) default NULL,
`bill_city` varchar(50) NOT NULL default '',
`bill_state` char(2) NOT NULL default '',
`bill_zip` int(5) unsigned NOT NULL default '0',
`bill_phone` varchar(20) default NULL,
`bill_email` varchar(50) NOT NULL default '',
`shipg_eq_bill` int(1) unsigned default NULL,
`bill_status` varchar(25) default NULL,
`CC_alerted` int(1) default '0',
UNIQUE KEY `bill_id` (`bill_id`),
UNIQUE KEY `ref_no` (`ref_no`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=132 ;


CREATE TABLE `shipp_info` (
`ship_id` int(10) unsigned NOT NULL auto_increment,
`bill_id` int(5) unsigned default NULL,
`ship_name` varchar(100) NOT NULL default '',
`ship_address_1` varchar(100) NOT NULL default '',
`ship_address_2` varchar(50) default NULL,
`ship_city` varchar(50) NOT NULL default '',
`ship_state` char(2) NOT NULL default '',
`ship_zip` int(5) unsigned NOT NULL default '0',
`ship_phone` varchar(20) default NULL,
`ship_email` varchar(50) NOT NULL default '',
UNIQUE KEY `ship_id` (`ship_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=27 ;


Thanks for any help!

-afan