partition by date then add partition does not work

[John Mizell]

First I alter my table with the following partitions:

alter table traninfo PARTITION BY RANGE (TO_DAYS(timestamp))
(
PARTITION January08 VALUES LESS THAN (to_days('2008-02-01')),
PARTITION February08 VALUES LESS THAN (to_days('2008-03-01')),
PARTITION March08 VALUES LESS THAN (to_days('2008-04-01')),
PARTITION April08 VALUES LESS THAN (to_days('2008-05-01')),
PARTITION May08 VALUES LESS THAN (to_days('2008-06-01')),
PARTITION June08 VALUES LESS THAN (to_days('2008-07-01')),
PARTITION July08 VALUES LESS THAN (to_days('2008-08-01')),
PARTITION August08 VALUES LESS THAN (to_days('2008-09-01')),
PARTITION September08 VALUES LESS THAN (to_days('2008-10-01')),
PARTITION October08 VALUES LESS THAN (to_days('2008-11-01')),
PARTITION November08 VALUES LESS THAN (to_days('2008-12-01')),
PARTITION December08 VALUES LESS THAN (to_days('2009-01-01')),
PARTITION January09 VALUES LESS THAN (to_days('2009-02-01'))
)
;

Which works just fine.

Then I want to add more partitions:
mysql> alter table traninfo add partition (February09 VALUES LESS THAN (to_days('2009-03-01')));
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'February09 VALUES LESS THAN (to_days('2009-03-01')))' at line 1

I am under the understanding that you should be able to add partitions as long as they do not overlap. What am I doing wrong?

Mysql version 5.1.30 on centos 5.2.