Jauthentication Fatal Error

My Links is

http://officespaceleyland.com/administrator

When I Tried To Log in the backend i am getting the following error

Fatal error: Class 'JAuthentication' not found in /home/officesp/public_html/libraries/joomla/application/application.php on line 640

I reinstalled that php file again but still same error not sure what has gone wrong.

Is there anyone around to help

You have a database error in your login page anyway so rather then worrying about authentication i will worry about why you seeing that sql error..

If you dont have a lots of data to loose i would suggest a reinstall as it maybe your database is corrupted, if you do still want to fix it use phpmyadmin and look for "uip25_modules" as error suggest it cannot find such tables in your joomla database...

Hi Thank You I am doing a reinstall as it is a new website. While Installing The Prefix for the database is uip25_ am i doing it correct or do i need to change the prefix to jos

Well for security reasons you can use anything but few old modules or components etc dont use joomla standard and ask joomla config for current prefix rather they have a fixed sql using jos_ prefix in the code. So if you dont have such addons or modules or components which i doubt you will then you can use anything...