Duplicate entry '3841' for key 1 in query

[mikeh]

I am trying to get my site running in a cluster. I dumped the site, changed ENGINE from MyISAM to ndbcluster and reloaded.
All seemed well until I tried to update a table..

Duplicate entry '3841' for key 1 in query:
REPLACE INTO config (name, type,value,blob_value) VALUES ('root_url', 0, 'http://www.amazon.com';, NULL)

This is how table was created;

CREATE TABLE `config` (
`config_id` int(11) NOT NULL auto_increment,
`name` varchar(64) NOT NULL default '',
`type` smallint(6) default '0',
`value` varchar(255) default NULL,
`blob_value` blob,
PRIMARY KEY (`config_id`),
UNIQUE KEY `name` (`name`)
) ENGINE=ndbcluster DEFAULT CHARSET=latin1 AUTO_INCREMENT=3841 ;

Can anybody throw any light on this error, It happens for any update to this table.