I found a good article here:
http://www.openwin.org/mike/index.ph...col-requested/
which says...
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In MySQL Version 4.1, the MySQL developers upgraded the process used to authenticate users. The password hash used in authentication was increased from 16 to 41 bytes, and the hashes were made more secure.
One side effect of this is that versions of MySQL clients older than version 4.1 cannot talk to a version 4.1 server, because old clients will not be able to give the proper password hashes.
There are two ways to deal with this. The first way is to upgrade your client library as the error message suggests. This is a good idea because you will then be using more secure authentication and reaping the benefits of newer client libraries. PHP users should note that only the MySQLi library uses a new client library.
The second way is to force the 4.1 server to use the older authentication protocols. This can either be done on a per-account or server-wide basis.
To configure a single account to use the old protocols, set the password for the account using a 16 byte hash:
mysql> SET PASSWORD FOR ’some_user’@’some_host’ = OLD_PASSWORD(’mypass’);
When MySQL detects an 16 byte hash, it will authenticate the account using the older password hasing system and older client applications will be able to connect.
To configure MySQL to use the older authentication scheme on a server-wide level, add old-passwords as an option in your configuration file under the [mysqld] section. This will cause the server to set all passwords using 16 byte hashes, which will force the older authentication scheme. Any existing 41 byte passwords will need to be reset in 16 bytes using the SET PASSWORD syntax described above.
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hope that helps you.