The application that you're asking about seems to have been discontinued. Even though for some reason, you can still pay for Musicator (lovely company), every other page on the website no longer works, so you can't download a trial or contact the developers. Furthermore, the last update was all the way back in 2009, so the best advice that I can give you is to try using an alternative application such as Sibelius, MuseScore (free) or MagicScore.
