If you are getting unspecified errors look in your error logs to se if there are any other errors that can point you in the right direction.
You get there by going into start, right click on my computer and choose manage.
Also look in your reliability and performance logs.
Check your services to enure the correct ones for sharing are turned on.
Check the tutorials on this website.
Services System Health Report Simple File Sharing - Enable
This is just a couple to look at.