Norton Ghost 14 missing backups

I have a clean install of windows XP and Norton Ghost 14.  I was able to successfully backup my two internal drives to an external USB drive if I run the backup manually.  However, my scheduled nightly full backups are not running at all.  I have power savings disabled so my computer does not power down at night, only my screen saver kicks in.  Each morning, my computer shows the following error:

 

"The last scheduled backup of OS (C:\) was missed."

 

That's the only error that shows and I have full logging turned on.  In my event logs, there are no errors, just information notices that say "Norton Ghost Service Started Successfully" periodically.

 

Are there additional settings or modifications I should check to ensure this backs up at 3:15AM every day?

 

Many Thanks,

GL