Error when trying to install SQL Server 2012 Ent in to a Server Core 2008 VM
Nothing seems wrong with your setup. I too am doing the training and noticed the books had some errors in them. 

But notice the difference between the 'WHOAMI' output, and your installation command line. 
The book has several typos where it calls the domain: Contoso, while before you created a domain called Contso. 

Change your command line to: /SQLSYSADMINACCOUNTS="Contso\kim_akers" and it should work.