I encourage anyone updating code as prescribed in this post to do so in an extension rather than modify a core file.

Thank you for sharing this knowledge!

Regards,
Ben

This is how I did it:
http://mysillypointofview.richardferaro.com/2010/03/24/how-to-fix-magentos-admin-login-failing-no-error-message-on-localhost/

I have a contact form at the sidebar of my magento.

But when the page loaded, it automatically displays the midle of the page where the mini-contact form is placed.

I saw that the insertion point was on the first textbox of the mini-contact form even though i didnt click on it.

See the problem here. http://amazingpropertyinflorida.com/amazingpropertyinmarbella/

When the page loaded, it does not display the header and menu but it will display the midle part of the web.

I hope you got what i want to say. and i hope you can help me with my problem.

Thanks in advance.

app\code\core\Mage\Core\Model\Session\Abstract\varien.php
$this->getCookie()->getDomain(),
$this->getCookie()->isSecure(),
$this->getCookie()->getHttponly()
Comment these lines line (may be at line 78…);

So after doing r&d i found out the solution

search for “// session cookie params” line in app\code\core\Mage\Core\Model\Session\Abstract\varien.php

change
$cookieParams = array(
‘lifetime’ => $cookie->getLifetime(),
‘path’ => $cookie->getPath(),
‘domain’ => $cookie->getConfigDomain(),
‘cookieParams’ => $cookie->isSecure(),
‘httponly’ => $cookie->getHttponly()
);

to

$cookieParams = array(
‘lifetime’ => $cookie->getLifetime(),
‘path’ => $cookie->getPath()
);

and comment the below mentioned code
line number 86, in my file

/* if (!$cookieParams['httponly']) {
unset($cookieParams['httponly']);
if (!$cookieParams['secure']) {
unset($cookieParams['secure']);
if (!$cookieParams['domain']) {
unset($cookieParams['domain']);
}
}
}

if (isset($cookieParams['domain'])) {
$cookieParams['domain'] = $cookie->getDomain();
}
*/

now login as admin, it will work