Not sure I've set up everything correctly as I've just installed VirtualMinPro and created a domain for testing purposes. I tried to Change Password for the domain and I got the following message:
Your password for walrusonline has been changed successfully. Any telnet, SSH, FTP or POP3 logins made from now on will require the new password.
However, your Samba password was not changed :
startsmbfilepwent_internal: file /etc/samba/smbpasswd did not exist. File successfully created.
Failed to find entry for user walrusonline.
Failed to modify password entry for user walrusonline
If the file doesn't exist, you probably should assume that there is no Samba password and just print a message that no password for Samba found.
Or, maybe smbpasswd should exist after installing VirtualMinPro?