This is because you are using a old version of svnversion.
Try to open the Command Line Prompt, navigate to the svnversion directory and do the same job as the MSBuild.
CMD:
cd C:\ProgramFiles\TortoiseSVN\bin [ENTER] svnversion C:\VisualStudio\Projects\YourDirectory [ENTER] SVNVERSION should answer why its not working, in my case was by E155021: This client is too old to work with thew working copy at...