The only issues with the backup service I see in the event log:
Event Type: Error
Event Source: HomeServer
Event Category: Backup
Event ID: 267
Date: 1/10/2013
Time: 2:56:33 PM
Client Backup server failed at d:\wssg_src\whs_pp2\qhs\src\backup\server\service\qsminterface.cpp(333)
For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.
-------------------------------------------------------------------------------------------------------------------------------
Event Type: Error
Event Source: HomeServer
Event Category: Backup
Event ID: 275
Date: 1/10/2013
Time: 2:56:33 PM
No volume contains enough free space to create the client backup database. At least 20GB is required.
For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.