To use svn+ssh:// style svn URLs on the Windows command-line, ensure the %SVN_SSH% environment variable is properly set:
- It must contain the fully-qualified path to the SSH client (typically plink.exe from the PuTTY suite)
- The path must be written using forward-slashes instead of the Windows-standard backslash.
setx SVN_SSH "C:/Program Files (x86)/PuTTY/plink.exe"
Source: http://stackoverflow.com/questions/10598069/svnssh-and-sourceforge