 <p>I don't have any trouble getting a connection using</p> <pre><code>C:\Program Files\PuTTY&gt; putty -ssh -l &lt;username&gt; &lt;hostname or host ip&gt; </code></pre> <p>The only things that leap to mind are either 1) a problem with the script used as part of the <code>-m</code> argument, or 2) an incorrect use of capitals. Could the error message be generated by the script rather than the command? Could you possibly have used </p> <pre><code>C:\Program Files\PuTTY&gt; putty -ssh -L &lt;username&gt; &lt;hostname or host ip&gt; </code></pre> <p>A capital <code>L</code> is for a port-forwarding setup, while lowercase <code>l</code> is for specifying a login (username).</p> <p>A couple of notes:</p> <p><code>plink</code> does a similar job without opening a new window. Might be worth exploring, but the commands are pretty much identical.</p> <p>It's generally not a good idea to put plaintext passwords on the command line. You would be better off exploring keys, especially if this is for an automated process. A quick search will turn up a variety of links, but you'll need to check for the best way to handle your particular situation. If you want this to operate as part of an automated script, you'll do different things than if you want to run it as part of an interactive session where you already have Pageant running.</p> <p>If you do go with keys, then your command line becomes</p> <pre><code>putty -ssh &lt;username&gt;@&lt;host&gt; -m &lt;script on local machine&gt; </code></pre>