Hello e11even, and welcome to Seven Forums.
That error means that the C:\Users\Sean\Desktop\2013-01 (Jan)
folder you have included to be backed up no longer exists on your computer.
You should be able to use the Change settings
option (step 4 in tutorial below) to setup your backup again without the missing folder being included anymore. Afterwards, you should be able to create backups without getting this error. Backup User and System Files
Hope this helps,