Less than four months after taking the top spot at the vidarm of 20th Century Fox, worldwide prexy Jeffrey Yapp has ankled his post. It’s the second top-slot exit this year, as Yapp replaced Bob DeLellis, who left the studio in May to pursue other opportunities.Yapp, who was chief of the vidarm’s international unit and added the reins of the domestic homevid operation in the appointment, received high marks from the studio brass for substantially growing the international division. Under Yapp, the arm doubled its revenues, and he created the first international direct-to-retail distribution system. The former Pizza Hut and Gallo Winery marketing whiz was also among the first wave of execs to focus on the untapped potential of foreign markets to the homevideo industry. A spokesman for 20th Century Fox Home Entertainment confirmed Yapp’s departure, but the studio issued only the following: “Mr. Yapp is under an exclusive contract with Fox through Oct. 16, 1999.” The departure comes as the studio’s homevideo operation is at one of its hottest moments, thanks to the release of the “Star Wars Trilogy” vidsets and its recently bowed line of family fare titles through a deal with Saban, all on the heels of last year’s vidmonster “Independence Day.” The actioner is the industry’s bestselling live-action vid, with an 18 million-unit tally.