Hmmm… It seems like there is already an admin user in your OJS database. Could you take a look in your database table users? Did you maybe try to do the installation several times i.e. could it be that first something went wrong? Maybe you should drop that database, create a new one and start a clean installation again?
Yes, I understand that there is already an admin user in your OJS database
but how I can remove it? I tried many time to install,
I drop the database start a clean installation but still having same problem