Well, I'm not doing too well lately - not only did I misundertsand what you wanted but I obviously didn't fully understand the code. But I did try putting this html file on my local machine:
Code:
<html><body>
<form action="http://*************/forum/login.php" method="post" onSubmit="md5hash(vb_login_password,vb_login_md5password,vb_login_md5password_utf)">
<p class="content">
<script type="text/javascript" src="http://losttv-forum.com/forum/clientscript/vbulletin_md5.js"></script>
Username: <br><input type="text" class="content" name="vb_login_username" id="navbar_username" size="30" accesskey="u" tabindex="1" value="Username" onFocus="if (this.value == 'Username') this.value = '';" /><br>
Password: <br><input type="password" class="content" name="vb_login_password" size="30" accesskey="p" tabindex="2" /><br>
<input type="checkbox" name="cookieuser" value="1" tabindex="3" id="cb_cookieuser_navbar" accesskey="c" checked="checked" />Remember Me</label><br />
<input type="submit" class="button" value="Login" tabindex="4" title="" accesskey="s" />
<input type="hidden" name="s" value="" />
<input type="hidden" name="do" value="login" />
<input type="hidden" name="forceredirect" value="1" />
<input type="hidden" name="vb_login_md5password" />
<input type="hidden" name="vb_login_md5password_utf" />
<input type="hidden" name="url" value="http://*************/forum" />
</form>
</body></html>
It's just your login form with a couple changes (and I replace my site iwth *'s). When I copied your code it logged me in but sent me back to the above login page. So I added the "url" hidden field with my site's home page and then it sent me there with the "Welcome $username" message. I have no idea if this will help you at all - maybe it's just saying that it worked for me but it still doesn't work for you.
Anyone else?