Ghost 15 Skipping my C drive

I am running Ghost 15 SP1 on 64 bit Windows 7 configured with a 1 TB Raid 0 array (HP Pavilion Elite)

 

I configured a single drive backup job to backup my C and D drives to an external HD.  The job is scheduled to run 3 days a week at noon.  However, whenever the job runs, its only backs up the d drive, and skips over the c drive.  When I run the job manually, it wil pick up the c drive most of the time but not always.  I use this computer al the time so I know the contents of the c drive are changing so it should create an incremental.  Any thoughts on what is going on here?

 

Note I also had this problem on my previious computer which was an older Gateway, 32 bit Windows 7 machine.  It too had a Raid 0 array so I am wondering if this has anything to do with the problem?