I often need to share a folder on one of my Raspberry Pi computers. Here is the process I use:
Install the software:
sudo apt-get install samba samba-common-bin
Check that the daemons have been started:
sudo service samba status
Make a folder to share:
Add your share to /etc/samba/smb.conf
[My Share] comment=My Share path=/home/pi/share browseable=Yes writeable=Yes only guest=no create mask=0777 directory mask=0777 public=no
Set a samba password:
smbpasswd -a pi
Restart samba daemons:
sudo service samba restart
Now you should be able to see your share over the network and log in using your user/password entered above.
If you cannot see the share, make sure that you have restarted the daemons and that they started back up. If you can see the share but cannot access it, check that the path you entered actually points to a valid location and that your user has the rights to access it.
The next step is to have a look in the log files which are located under /var/log/samba