On LQ, it's preferred to ask and answer questions on the forums, so that other visitors can benefit from the answers.
You questions are kind of wide-ranging and could stand to be a little more detailed and specific. Here are some hints about how to ask good questions
As regards Samba, Samba by Example (PDF)
is my favorite reference.
At first guess, I'd expect that your Windows accounts don't have rights on the Linux box or passwords in /etc/samba/smbpasswd.
Here's a good general reference: http://tille.garrels.be/training/tldp/