Running a query in phpmyadmin works, but same query run by mysql_query() function in php fails.

The php code is this
AddChildNode();
function AddChildNode() {
mysql_query('LOCK TABLE tree WRITE;

SELECT @myLeft := lft FROM tree
WHERE CategoryID = 2;

UPDATE tree SET rgt = rgt + 2 WHERE rgt > @myLeft;
UPDATE tree SET lft = lft + 2 WHERE lft > @myLeft;

INSERT INTO tree(Name, lft, rgt) VALUES("FRS", @myLeft + 1, @myLeft + 2);

UNLOCK TABLES;');

}
$result = mysql_query('SELECT Name, lft, rgt FROM tree;');
while ($row = mysql_fetch_array($result)) {
echo $row['Name'].' '.$row['lft'].' '.$row['rgt']."\n";
}

If u want to test here is the table
CREATE TABLE `tree` (
`CategoryID` int(5) NOT NULL auto_increment,
`Name` varchar(100) NOT NULL default '',
`lft` int(5) NOT NULL,
`rgt` int(5) NOT NULL,
PRIMARY KEY (`CategoryID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;


INSERT INTO `tree` VALUES (1, 'Parent1', 1, 2);
INSERT INTO `tree` VALUES (2, 'Parent2', 3, 4);
INSERT INTO `tree` VALUES (3, 'Parent3', 5, 6);
INSERT INTO `tree` VALUES (4, 'Parent4', 7, 8);

Is there some special syntax that i have to use with mysql_query?

Never mind it cannot take multiple lines.
I have to run each line separately. then it works