Are you sure you have the title correct? Bob Powers and Julia Gorchakova do several videos for DanceVision (at www.dancevision.com ), but I didn't see the title you mention. While I don't know for certain, I have the impression these dancers would sign exclusive contracts when making these videos -- in other words, I think the chances of a current tape by Bob Powers being available through another publisher is remote.

If the tape is discontinued/out of print, DanceVision may be able to recommend a current counterpart, or you might find a "used" copy via ebay or some other means -- but I'd check and make sure you had the right title first, and contacting DV seems a good place to start