When logged in as root I get the following errors trying to set up a new password:
Renato:~ root# smbpasswd
New SMB password:
Retype new SMB password:
dyld: smbpasswd Undefined symbols:
/etc/pdb/opendirectorysam.so undefined reference to
_get_opendirectory_authenticator expected to be defined in the executable
this is a mac osx issue it appears. We don't ship that pdb module.
You might need to follow up on http://developer.apple.com/darwin/
or with Apple support.