[Koha] Access denied for user 'root

Dear friends, We are using Koha 10.02 on Ubuntu 12.04 LTS. During the installation I used Ubuntu MySQL Security Tweak from this documentation http://wiki.koha-community.org/wiki/Koha_on_ubuntu_-_tarball The anonymous connections were removed. But now I need to connect Koha database with a Mysql -u root -p command. As would be expected mysql has generated an error. ************************************************************************ 'Access denied for user 'root'@'localhost' (using password: YES)' **************************************************************************** ** How can I fix this problem and over again to use a mysql -u root -p command. Thank you for your help! Araik.