sfz+ question

Why won't sfz+ play, or even open any of the sfz files in the multisamples folder that came with Dimension Pro?

The sfz+ player was programmed quite a while back, using a version of the .sfz format known popularly as "SFZ 1.0". It's a powerful version of the 'language' in its own right. But Dimension Pro, and most of the later Cakewalk synths, use an enhanced command set. Many of the commands remain the same, or have slight differences in the syntax used. But a lot of additional functionality has been introduced in "SFZ 2.0", and that's not backwardly compatible with older players like sfz+.