Cannot write to windows share ntfs folder from mac

When you created the shared folder on Windows, you had the opportunity to change the default permissions on the share (which grants Everyone read-only access). You should go back to the share properties, and click on Permissions and grant Full Control permission to one or more Windows users known to your machine. Or you can give Everyone Full Control (but be careful what data you expose).

When you access the share from another machine (even a Mac) you should be required to authenticate with the Windows machine, at which time you would enter a username/password for a user known to the Windows machine. Then you will have write access.

The underlying volume format won't matter for SMB shares. It's definitely a permissions issue. Keep in mind that share permissions are separate from disk permissions set on files and folders. You can try setting up simple file sharing on your Win7 machine. Or if you're using password protected sharing, then the easiest thing to do will be to create a user account on you Win7 machine with the same logon name and password as your OS X user and make sure the user account has permissions to the share and folder.