Perform Complete PC Backup on Vista

Need to have a DVD or HDD with sufficient disk space.

Set the followings services to "Manual" startup:

Background Intelligent Transfer Service (BITS)
Block Level Backup Engine Service (wbengine)
Base Filtering Engine (BFE)
Windows Backup (SDRSVC) Service
Virtual Disk (vds) Service
Volume Shadow Copy (vss) Service

Also check:

DCOM Server Process Launcher (DcomLaunch)
Remote Procedure Call (RPC)
Have you tried with UAC disabled ?