Access Denied when attempting to SSH via PUTTY

Sorry if this is a simple/dumb question, but hopefully someone can help.

I'm attempting to access my Jailbroken ATV2 and want to update to v5.01 and when I attempt to SSH via PUTTY it says ACCESS DENIED when typing in my ssh root@(my ip address).

I am able to open a connection to my ATV2, but when I first connect a SECURITY BREACH WARNING SIGN pops up saying that the host key's name is not recognized. Does this have anything to do with it?

My ATV2 was previous Jailbroken and XBMC v 4.0 was loaded on it, just wanted to update to v5.0.

Thanks ahead of time for any help.

MBarr9or