im getting an error in "upgrade_start.php" when upgrading from 2.6 to 2.7 and same error in "install_create_tables.php" when installing from the begining, what could it be ?

Code:
ERROR: Unable to execute query

SELECT user_password,user_salt FROM `users` WHERE
               `user_name`='ChaosMage'
Table 'rutube.users' doesn't exist
in 2.6 i didnt have table "users".

help plz