Hi AlexandrP,
Just stumbled across this, so appreciate you posted a while ago and probably sorted this.
Netsight initially uses the account you are currently logged into your operating system with (as already mentioned) as the account to log into after an install. You must use an account that has a password set otherwise you will get this message - I know as I've done it myself:)
Set a password on your account and reinstall Netsight, then you should be able to login.
