Can't add samba user and hostname problem

[l2oi3]

disclamer:this might be the wrong section? if so sry

I'm new at this whole linux thing and have been following the following guide to set up a home fileserver:
http://www.howtoforge.com/ubuntu-home-fileserver-p3

when i got to the step where it told to me to add the user family by entering smbpasswd -a family into the console. When I enter it the console asks for the a password which i enter, and then says Failed to modify password entry for user family

Any ideas?