I want to know if I can glue down 3/4 cherry (5 1/4 plank) over the exhisting (tar based) glue from the 50's. It seams to be an excellant vapor barrior, has been there a long time & has the conrete sealed very well. Would a urathane glue adhere to that?

Nope! Black asbestos cutback adhesive, is a big time bond breaker. Remove as much as possible(watch the asbestos laws) and encapsulate with a product like ARDEX SD-F.

Or, better yet, reactivate that cut back adhesive with kerosene and cover it with 3/4" plywood and nail it/tapcon it down. Then you can nail down your floors. Or use a floating plywood subfloor.