Thanks for pointing out this issue.
What happens is for some reason my client cannot handle IGNORE message.
Can you tell me what scenario are you using, SSH terminal, SFTP or port forwarding?
Also, did you try to connect to other SSH server to see if it would work?
If its possible, can you turn logging on when you connect using putty and send it to me, if its not a security risk there of course?
Do you you use source or binary version, if you using source can you let me know what line exact it failing?
Also, do you happened to know what authentication methods suported by the server? password, private-key etc'.
And las question, what server version you trying to connect to?