Logon Failure: the user has not been granted the requested logon type at this computer.

To enable simple file-sharing across a network without user accounts then proceed with the following.

* If password-protected sharing is turned on, the person you want to share with must have a user account and password on your computer for full access to shared items. Password-protected sharing is located in Control Panel under Advanced sharing settings. It's turned on by default.

Link to more details:

http://www.howtogeek.com/howto/windows-7/share-files-and-printers-between-windows-7-and-xp/