"Burden of Dreams" documents German director Werner Herzog's journey into his own heart of darkness: a five-year struggle to film the surreal "Fitzcarraldo" in primitive, perilous Peru.

Herzog, who commissioned Les Blank to make the documentary, quickly becomes as obsessed as "Fitzcarraldo," a penniless Irishman sworn to build an opera house on the Amazon for his idol Caruso. First, though, Fitzcarraldo must portage a 320-ton steamship uphill to reach a forest of rubber trees.

When the film's star Jason Robards comes down with dysentery, filming halts and costar Mick Jagger quits to record an album. Herzog cuts the Jagger role and re- casts Klaus Kinski as Fitzcarraldo. Next, native politics force the crew to a new, remote location.

Murphy's law shadows Herzog, who insists on real steamship footage. It's the film's central metaphor and Herzog, like Fitzcarraldo, won't give it up: "If I abandon this project, I abandon my dreams."

Most of all, "Burden of Dreams" is a candid portrait of Herzog -- stubborn, brilliant, vivid and remorseful. "I am running out of fantasy. I don't know what will happen now," he says as the film buckles under him. His extras go off to fight a rival tribe. The engineer quits when Herzog insists on moving the boat in a way that endangers the cast. And his financial backers jump ship.

As drought, death and injury stalk him, Herzog talks of going to an asylum. "Nobody on this earth will convince me to be happy about this," he says of his film, finally completed in November 1981. BURDEN OF DREAMS -- At the Inner Circle.