I just used 5.1 with Oracle VM and it works fine. The 5.2 ova file does not work. I got the 5.2 file from here: http://www.stp.dias.ie/~vbraun/Sage/sage-5.2.ova
I was unable to fine the 5.2 .ova from the main page and navigate to it. The above link was provided to me in the answers.
Any help would be greatly appreciated. Am I using a beta version of 5.2? I need the log scale feature of 5.2.