In Band in a box, if you have only midi tracks then save it by choosing "Make a standard midi file" and save. I've used the BIB midi files directly in Sonar for every version of Cakewalk from 4 to Sonar X3 with no problems. However, if you have audio in the BIB project,that's a different ballgame. Sonar can't open BIB project files but RealBand can. Only way I know to get that into Sonar is either to save the whole thing as a wave file, or move it track by track.