Troubled women's athletic shoemaker Ryka finally found its Prince Charming, in the guise of Michael Rubin, a 22-year-old Philadelphia entrepreneur. Rubin heads KPR Sports International, a privately held footwear distributor claiming 1994 sales of $27 million. He will give Ryka loans and other credit facilities worth $8 million in return for up to 40% of Ryka stock. The deal, which came five weeks after a pact with L.A. Gear collapsed, buoyed Ryka's stock, which had been nearing zero. And it kept founder Sheri Poe employed: She remains Ryka's chief spokes-person and a board member.