Problem using Plink remote commands

I'm not sure this is the right place for this, but there doesn't seem to be a place to get help with Plink specifically.

I'm trying to write a batch file that will use Plink to tunnel to Server 1 via ssh, then use Plink's remote command function to tunnel from Server 1 to Server 2. Here's the code I'm using:

start D:\Temp\plink.exe -A -P [port] -D [host]:[port] [username]@[server1] ssh -p [port] [username]@[server2]

I should mention that when I log into Server 1 through Plink and then manually enter the ssh command, it works fine. I've tried putting the ssh command in quotes and putting it in a separate file accessed with the -m flag, but the batch file always opens a window that says "Warning: Permanently added '[server2]' <RSA> to the list of known hosts" and then hangs. 

I'm completely and utterly baffled. Any ideas?

Erin