seperate login form redirects to itself after login

[silver.fox1969]

Hi I have created this form for my login however after the user tries to login they see the window thank you for loging in but then it redirects back to itself

	<!-- Login Form -->
<script 

src="/forum/clientscript/vbulletin_md5.js" 

type="text/javascript"></script>
<form action="/forum/login.php?do=login" method="post" 

onsubmit="md5hash(vb_login_password,vb_login_md5password)">
<input name="vb_login_md5password" type="hidden" />
<input name="s" type="hidden" value="" />
<input name="do" type="hidden" value="login" />
<input class="bginput" name="vb_login_username" size="12" 

type="text" /><br />
<input class="bginput" name="vb_login_password" size="12" 

type="password" /><br />
<input checked="checked" class="bginput" name="cookieuser" 

id="cb_cookieuser" type="checkbox" value="1" /><span 

class="smallfont">Use Cookies</span>
<input class="button" type="submit" value="Login!" />
</form>
			</div>

any ideas I am using version vb 4.1.8

thanks