eLicenser???

Hello, I installed CUBASE elements 6 and it worked for a while, but now it stopped working due to a problem associated with elisenser. Am I supposed to buy something like this?

http://www.elicenser.net/en/download_archives.html

Could you advise?

No, you´re not supposed to buy something like this…
And since you´re not posting any useful info on what the actual problem exactly is, it might be difficult to advise…

Cubase Elements doesn´t need a dongle USB (only Artist and full version). Elements uses only a licenser software system.

Did you tried to reactivate Cubase Elements in your “My Steinberg” area?