Check the permissions of the share and add the login to it , then type the login name exactly as it appears in brackets here:
Also, things to note.
1. Don't rely on Everyone having full control
2. The printer requires the login to have a password, doesn't matter what the local user does, if you want to scan, the loogin used by the printer needs a password.
3. Don't share a folder within a users folder (My Documents/ Desktop etc etc) If they want scans going to a folde ron the desktop, share it from the root (c:\scans) and right-click Send to > Desktop (create shortcut)
4. Generally speaking, if you are on Win XP or older the port is 139 for SMB, Vista and higher is port 445.
5. Everything is case sensitive