To test the connection we will use PuTTY. Start the program and on the Session tab set the hostname to the name or IP address of your server, the protocol to SSH and save the session as SvnConnection or whatever name you prefer. On the SSH tab set the preferred SSH protocol version to 2 and from Auth set the full path to the .PPK private key file you converted earlier. Go back to the Sessions tab and hit the Save button. You will now see SvnConnection in the list of saved sessions.

Click on Open and you should see a telnet style login prompt. Use svnuser as the user name and if all is well you should connect directly without being prompted for a password.

You may need to edit /etc/sshd_config on the server. Edit lines as follows and restart the SSH service afterwards.

PubkeyAuthentication yes
PasswordAuthentication no
PermitEmptyPasswords no
ChallengeResponseAuthentication no