I am trying to ssh a remote box from putty but I am getting following error.

"No supported authentication methods available"

I don't have access to the server so I must have make my ssh client compatible to ssh server.

This is the trace from another client

[SSH] Protocol Version 2 (OpenSSH_5.3p1 Debian-3ubuntu6)
[SSH] Cipher: aes128-ctr
[SSH] FAIL: Unable to authenticate
[SSH] INFO: DISCONNECT

How can I fix it?

sshd service should be running on the server to be able to connect. can you verify this? try telnet also.

Assuming it is running, what authentication methods is it configured to accept? Password authentication will work with Putty without much configuration. If you are set up to only use key based authentication, you need to convert the standard (Linux) format key into the form used by Putty. Any of the several how to documents on SSH with Putty should show you how to convert the certificate.

You can also debug the process by using the -V command switch. This will provide you with a lot more information regarding where the connection is failing.