"RKO 281" was inspired by but is not one-tenth as good as a 1996 PBS documentary called "The Battle Over 'Citizen Kane.' " HBO's film, just under 90 minutes long and premiering at 8 tonight, not only is unworthy of "Citizen Kane"--a towering landmark in movie history--it's also unworthy of the documentary. Thus do two good deeds fail to go unpunished.

"Citizen Kane," which Pauline Kael has called the greatest American film of the sound era (that's anything from 1927 on), marked, of course, the Hollywood debut of Orson Welles, who in his mid-twenties was already considered a modern marvel for his acting and directing in theater and radio. Kael has also perceptively noted that "Citizen Kane" is a playful and entertaining masterpiece, not a solemn and self-important one.

That fact, among others, appears to have escaped those who made "RKO 281," the title standing for the film's production number at RKO Studios, where it was made in 1941. Welles said he found a movie studio to be the greatest toy train set a boy ever got to play with, but in the HBO film he's pretentious and humorless about the whole thing. Words are put into his mouth that the real Orson Welles would likely never have said.

"Kane" is still fun to watch partly because Welles and his colleagues, some as new to films as he was, had a ball pushing the technical limits of moviemaking. Little of this comes through in "RKO 281," in which it's made to look as though Welles knew he was creating A Great Film at the time. It also looks like he had an obsessive vendetta against William Randolph Hearst--the corrupt press baron on whose life Charles Foster Kane's is partly based.

Hearst was just a convenience for Welles and the brilliant Herman J. Mankiewicz, co-writers of the "Kane" script. They wanted to tell the story of a "great man" from several points of view. In the original trailer for "Citizen Kane," characters from the film describe him as noble, evil, generous and selfish. Welles himself, who plays the role, says Kane was a heroic figure "and a dirty dog."

What was convincingly complex in "Kane" becomes simplistic and ridiculous in "RKO 281." Before the film starts production, the Welles character is seen railing against Hearst as "a modern feudal lord . . . an unfeeling monster . . . a hypocrite." Oh baloney. He may have indeed been those things, but destroying Hearst was probably the last thing on Welles's mind, if at all.

Hearst's empire was already crumbling, as "281" notes. As an artist, Welles always kept the audience in mind. He enjoyed surprising, entertaining, faking out and manipulating the crowd. It's insulting to suggest he'd waste his first chance to make a movie on trashing a fatuous windbag like Hearst.

"RKO 281" was written by John Logan, whose most recent movie was the flop thriller "Bats," laughed off movie screens throughout the country. Even more crucial to the failure of "281" is the casting of Liev Schreiber, an actor you've likely never heard of, as Welles. He doesn't suggest Welles in any convincing way, and he's boring, and he's horrid.

Too bad the producers couldn't get, or didn't want, Vincent D'Onofrio, a magnificent actor who did a delightful cameo as Welles in Tim Burton's warmhearted bio-pic, "Ed Wood." Wood was the world's worst director. But that was before Benjamin Ross came along. He directed "RKO 281."

James Cromwell is more credible as Hearst, the prudish, pious power-monger who lived with his mistress Marion Davies yet loved to lecture the world on morality. Davies (turned into fictitious opera star Susan Alexander in "Citizen Kane") is played kittenishly but less ditzily than usual by Melanie Griffith. John Malkovich is absurd, and sadly hammy, as Mankiewicz, who fought a lifelong battle with self-destructive impulses and his own talent.

Director Ross keeps cutting back and forth between Welles arguing with Mankiewicz and Hearst arguing with Davies. It gets to be monotonous quickly: "Dueling Duels." Sometimes the real Hearst says things that Kane also says, an easy fabrication in hindsight. All the fascinating lore and legends surrounding "Kane" were told more accurately in the documentary--and more dramatically, too. "RKO 281" isn't good enough to spit-shine "Citizen Kane's" shoes.