Hmmm it's a little weird that it's not there. If I could make a recommendation, download a theme by Collins521 his themselves are great. They are what I use all the time
The Dimension Today Plus theme was created by Blackberry that you downloaded from them it was available at mobile.blackberry.com at one point in time. Don't think it's there anymore , I also made a variation of the theme over at Pimpmyberry.