No such error. When I reboot my linode I get the putty security warning about the rsa key.
The putty security alert as seen in the link below is all that I get, which I guess is normal.
http://library.linode.com/networking/using-putty
When I try via putty, all I can do is, enter the IP, following which it asks me for the login, which I mention as root, followed by the password prompt, which I enter. The cursor stops blinking there and after about 30 seconds I get the windows pop up alert saying "Server unexpectedly closed network connection"