Convening a band is trickier without Craigslist, as this African-music doc demonstrates. Wendo Kolosoy (a.k.a. Papa Wendo), a prominent Congolese musician and sometime pugilist, roams the hardscrabble Kinshasa region, recruiting associates for a festive jam session. The music, a relative of Cuban rumba, is buoyant and soulful, and it creates a poignant contrast with the dire surroundings. But director Jacques Sarasin’s refusal to supply more than scraps of context—either about the performers or the politics of the civil-war–torn region—renders the film narratively limp.