my installation stops at a log-in page, not a dash board,i don't see a new user button in settings.is there a default log-in?
No default login. Page only appears if you had defined a user while logged in. If you have config privileges you can add new users.
Since I guess you don't know the login the only solution is to stop server, delete the user.sql file in <storagedir>/database and strat server again. Then you have no users and no login is required. user.sql will be recreated on startup. On linux systems storage dir is /var/lib/Repetier-Server and on WIndows c:/ProgramData\Repetier-Server.