The installation stops on 3rd step... The progress bar goes to about half, and then goes back to previous step. The database is created but there is no user inside, and some other fields are not set.
Yes we know this case, and You need to turn off display_errors in php.ini (how? You need to ask your hosting provider). Our database is quite big and if display_errors is on, while installation it throws some warnings (which should not display, and You dont see it in frontend) which affects the process.
Throw into ftp a simple test.php file with <?php phpinfo(); ?> inside and check for display_errors.