Re: File sharing in ubuntu & windows
You need to make sure that your share's permissions are set to read and write by all users, or specifically by a Samba user account that has the same name as the client's user account. Your users need to have Unix user accounts AND Samba user accounts.
If your server is Ubuntu, then you can install the "system-config-samba" package which makes it easy for you to create new Samba users and change the properties of shares.
I try to treat the cause, not the symptom. I avoid the terminal in instructions, unless it's easier or necessary. My instructions will work within the Ubuntu system, instead of breaking or subverting it. Those are the three guarantees to the helpee.