Can not create System Image with Windows 7, Error Code 0x8078002A

I’m having the same problem using  WD Caviar Green 3 TB SATA 6.0 GB/s WD30EZRX drive.  I want to use this drive like everyone else to do backups. I installed the drive in a external case and want to use it as an external drive. I have failed doing backup with Windows 7 backup utility with above error code.  I have also tried using Acronis ti 10.0 and it stops running. I’ve also tried USB 3.0 and 2.0 ports with same resultgs. I am very frustrated and don’t know where to turn for help at this point. I’m not looking to point fingers at anyone but just would like some answers. I’m using asus mb P7P55D-E LX which supports 6 GB/s disk transfer and usb 3.0 but not at same time.  Is it the size of the disk that’s causing the problem, maybe? Any help is appreciated.