error drupal after copy & paste folder, and same DB

I just copied and pasted the whole drupal content folder from my server to my localhost and also I dumped the DB to my localhost, but now my admin user authentication credentials are not working in the localhost.

I even reset my admin password (UPDATE admin SET pass = MD5('newpassword') WHERE uid=1;)

Also in watchdog table I am having this message when I try to authenticate:

"Session opened for %n开发者_运维问答ame."

Any ideas??

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The error was parameter $cookie_domain on file /sites/default/settings.php. it is working fine now