purge binary logs on master

[Ananda Kumar]

Hi All,
I using this command to purge binary logs on master, but i dont see the
binary logs getting deleted. These binary logs are listed in index file.
I am using mysql version 5.0.41 community version. Can you please let me
know if any thing else need to be done for this to work.

log-bin is enables.

PURGE MASTER LOGS BEFORE '2008-05-07 00:00:00';

regards
anandkl