Problem:
I had a new installation of magento. But I was unable to login as an administrator. I went to the admin login page, entered correct username and password but was redirected to the same login page. I could not enter the dashboard page. Error message is displayed when I enter wrong [...]

After  installing  Magento,  installation fails. There is error commenting
There has been an error processing your request
Exception printing is disabled by default for security reasons.
Error log record number: 281887837
This issue specially comes on localhost. Please forgive me if I left anything out.
You have not do much more for this problem.
Open this file ‘app\code\core\Mage\Core\Model\Session\Abstract\varien.php’ and comment these [...]