Samba shares may be encrypted by default check out the documentation on the Red Hat site (that's where I found it) on how to change the config files for Samba. If it's an XP machine you're trying to connect to, encryption is mandatory, and you'll have to config a password. Also, Check out http://www.redhat.com/docs/manuals/l.../ch-samba.html
for some good documentation. Make sure you read all of the docs. Hope this helps!