I've always used PuTTY (win32) in order to access my servers through SSH. Yesterday I upgraded OpenSSH on my server from 4.3 to 5.8 and it seems that PuTTY doesn't work now. It asks for a password, then confirms that the password is correct, and then gives the fatal error `Server refused to start a shell/command`.

When I try to log on with cygwin's OpenSSH, I have no problems.