Samba Testparm error

I have a recurring but slightly nonesensical error with Samba on Debian Etch

I have set up a very basic Samba configuration and have now uncommented all the references to passwords and encryption, nonetheless I still get this error message when I testparm :

'WARNING: passdb expand explicit = yes is deprecated'

Googling around I find some indications that this is bug. Is there a workaround or solution? Should I download an earlier version of Samba (I never had this problem using the same smb.conf with previous versions)?

thinking# testparm /etc/samba/smb.conf
Load smb config files from /etc/samba/smb.conf
Processing section "[homes]"
Processing section "[music]"
Processing section "[film]"
Processing section "[printers]"
Processing section "[print$]"
Loaded services file OK.
WARNING: passdb expand explicit = yes is deprecated
Server role: ROLE_STANDALONE
Press enter to see a dump of your service definitions