In order to use a universe in Crystal, you have to be able to connect to a BusinessObjects system to get the universe information. You also have to have installed the drivers to connect to universes when you installed Crystal (I don't think they're installed by default, but I may be wrong.)
Which version of Crystal are you using? The ability to connect to universes was added with Crystal XI, although I've heard that there are problems with it that were resolved in Crystal 2008.
-Dell