Replication stops on ALTER TABLE ; keep on getting "duplicate column names"

[Danny Sinang]

Dear All,
 
Here's our setup :
 
Master : MySQL v4.0.16-max-log
 
Slave : MySQL v4.1.10a-max-log
 
Everytime I do an ALTER TABLE on the master server, I get the following
error message on the slave server. 
 
050723  1:51:26 [ERROR] Slave: Error 'Duplicate column name
'TimefileDate'' on query. Default database: 'barmain_es'. Query: 'ALTER
TABLE `bartran` ADD `TimefileDate` DATETIME DEFAULT NULL AFTER
`SignOffBy`', Error_code: 1060

050723  1:51:26 [ERROR] Error running query, slave SQL thread aborted.
Fix the problem, and restart the slave SQL thread with "SLAVE START". We
stopped at log 'CentracDB-bin.013' position 2989111

Any idea on what could be causing this ?
 
Regards,
Danny