I use ubuntu so the configuration file could be different. If you are using gnome you should be able to share folders using samba through the gui.
Or you can edit the above file yourself.
If it the folder shows up on your windows machine must be some sort of permision error.
On your linux machine do
chmod 777 sharedfolder
this makes the folder read/write to everyone
Samba could also be blocking rw (read/write) so under your share module (in your smb.conf file and after the "[sharename]" part you need to add some other things
comment = hello
path = /home/me/downloads/
writable = yes
browsable = yes
read only = no
So maybe you just need to add writeable = yes or something similar. Also if you are using "user mode" (prob not on by default) you need a "write list = user1, user2"
Hope this helps