Were you getting an error message about there not being enough room to create the shadow copy?
If so, the problem is being caused by a Winre.wim file in the Recovery partition growing to a size that does not allow for shadow copies. Using a third party imaging software, increasing the size of the recovery partition, or perhaps replacing the larger one with a smaller one are the three options I can think of. The larger file appears to be adding files, probably driver files from the current install and thus, increasing in size.
I have had some occasional problems with error messages when using certain drives, which had worked find before and still had plenty of room available. Using another drive would normally clear this up and allow for the backup.
You might check the thread linked below. The part about WBAdmin is not really relevant to your situation, but the System Volume Information might be.
http://windowsforum.com/threads/win...ne-could-not-be-contacted.114876/#post-581779
You may want to add this arrow to your quiver of free backup tools. It's called Aoemi Backupper and a lot of people have suggested that it is a very good free option.I will try the 2 image backup tools that I have and do system image recovery and I will get back here to confirm which 3rd party backup tools work with 8.1. I have Macrium and Paragon. I'll see if I can get an Acronis...
You may want to add this arrow to your quiver of free backup tools. It's called Aoemi Backupper and a lot of people have suggested that it is a very good free option.
Personally I'm a big fan and user of Acronis True Image and have been using it since somewhere around version 6.... but it's not free (except for the 30 trial).