Sounds like a permissions problem. Can you post the output of "ls -l" of your share directory? You could also try to comment the 2 lines in the smb.conf (create and directory mask) and restart samba. Is it working then? btw which distro are you using? rasbian?
Owner and group of the folder are both the root-user, so editing or adding something wouldn't work with a different user. Change the owner to your user with "chown yoursambauser /media/.../shares" and try to write a test file. Btw are any files showing up when you connect via windows?
Did any one have a solution for this? I am having the same issue I have the smb.conf set up correctly I believe and I have added my user to samba as well. I can view the files from my windows machine but i cant write to it.