unknown authentication type?

Howdy:

Running PostgreSQL 7.2.1 on RedHat Linux 7.2.

Have a user who has installed the PostgreSQL ODBC
driver (7.01.00.05) on the Windows98 laptop.

I have configured the pg_hba.conf :

[snip]

# TYPE DATABASE IP_ADDRESS MASK AUTH_TYPE AUTH_ARGUMENT
host all xx.0.0.1 255.255.255.0 md5

[/snip]

On PostgreSQL, I've changed his password to reflect
any new changes and have made the configuration
to the ODBC driver under the ODBC Data Source area.
I've tested this against a few others, but it seems
to me that this should work (yeah, I know ...)

When he tries to connects to the database via MS Access 97
through the ODBC driver, he gets an error:

Unknown authentication type #201

My question: what, exactly, is the authentication type
referring to and how can I fix this?

Thanks!

-X