Step 6, red warning after step for “Download settings” is missing a point.
The necessary requirements for the folder are:
Folder must exist and be shared with permissions as follows:SMS Provider computer account and the user that is running the wizard to download the software updates must both have Write NTFS [and Change Share] permissions on the download location. For this tutorial it's "SMSAdmin" and the computer account for "CAS"
Everyone or at least Domain Users or Authenticated Users should have Read permissions
These requirments are described on TechNet at http://technet.microsoft.com/en-us/library/gg712304.aspx#BKMK_SUMSync and fixes the error due to lack of permissions as described in http://www.thelazysysadmin.net/2012/04/automatic-deployment-rules-download-failed-system-center-2012-configuration-manager/
I've had this error myself, and thought it would be useful for other to know about it.