Hi!
That message is because you only have been install your osticket but not start the service.
Follow these steps:
-go to your Control panel ( if you not know how, in your adress-bar, add "scp")
these window is the "staff side" osticket, the previous was the "client side"
- go to "admin panel", next select the radio button that said "Online".
Save changes, now you will be able to use your osticket ;)
-ATARSA