Can there be any truth to the rumor that Robert Altman will direct Robin Williams in the title role of "Popeye"? The Robert Altman who once directed comedies like "M*A*S*H" and "California Split" might have qualified for such a crucial assignment. The Robert Altman represented in the last six months by "A Wedding," "Quintet" and now the grotesquely inept romantic comedy "A Perfect Couple," opening today at area theatres, doesn't.

You wouldn't trust the fumbling, dithering director of "A Perfect Couple" with the last episode of "Hello, Larry," let alone the movie debut of a young comic star as inventive and agile as Williams. Altman's technique, always perilously intuitive and freefloating, breaks down before your horrified eyes in the would-be funny scenes of "A Wedding" and "A Perfect Couple." Everything is flubbed: lines, business, timing, character interplay.

What makes "A Perfect Couple" the most distressing fiasco in Altman's run of fiascoes is the fundamental innocuousness of the material.

"A Perfect Couple," contrived by Altman in collaboration with actor Allan Nicholls, is nothing but an ugly-duckling love story. Paul Dooley and Martha Heflin are cast as the leads, who are matched by a computer.

He's a middle-aged antique dealer bossed around by a tyrannical Greek American father. He is frustrated living at home, immersed in a traditional family circle. She's a back-up singer in a rock group bossed around by its young male lead. She is frustrated with the communal domesticity of the group, called "Keepin' 'Em Off the Streets."

The premise isn't subtle or profound. The characters are introduced on their first date, a symphonic concert at the Hollywood Bowl, and it seems only a matter of time before these shy, plain, lonely people hit it off, find the courage to assert themselves and leave the nests that confine them to establish their own habitat.

That's the way the story ought to evolve, but Altman's new-found clumsiness turns it into an ordeal. You wait for the underlying dignity to emerge in the flabby hero and the timid heroine, but nothing does. They're duller at the end than at the begining.

In "Marty", Ernest Borgnine told Betsy Blair that, "Dogs like us ain't such dogs as other people say we are." Altman has become so perserve that he makes Dooley and Heflin seem like uglier ducklings than the audience want to believe they are. He treats them as negligently as the thoughtless family groups that supposedly keep them from living their own lives.

The principal running gag is that the lovers can't get any privacy. God knows why. It's as if they'd never heard of motels in that part of the country.

The depictions of the Greek-American family and the counterculture family seem mean-spirited rather than funny. The domestic settings never impose themselves dramatically, since you don't believe them for an instant and can't understand what would prevent the lovers from breaking away if they were credibly tolerable.

What does impose itself is Altman's astonishing lack of facility. He makes a shambles of the hoariest commedy situations: the lovers missing connections by telephone, Dooley getting into a fight with a rival computer date played by Nicholls, people barging in on the lovers when they're about to hit the sack.

The wretched romantic comedy exposition is punctuated by song interludes in which we hear slurpy sentiments like "Won't somebody care?" and "Love is all there is" and "Won't you come into my fantasy?" There's no love story for these musical reveries to reinforce.

When someone warbles, "Now the party's over and everybody has gone on home," you can't help wondering if Altman appreciates the dreadful irony.