The executive at Columbia authorized to approve comedy projects should be quietly removed before foisting any more turkeys as hapless as the recently departed "Lost and Found" and newly arrived "Just You and Me, Kid" on an unsuspecting marketplace. Today's openings of the latter were, in fact, moved up as a direct result of the instant flop of the former. Columbia has done it again, leaving virtually the same theater-owners holding the bag.

"Just You and Me, Kid" brings together an unpromising geriatric-juvenile team, George Burns and Brooke Shields. He plays a garrulous, twinkly old entertainer, she a sullen but salvageable delinquent on the run. Fleeing from a drug pusher she has supposedly ripped off, the fugitive teen finds a hiding place in the octogenarian's Pierce-aArrow. When he discovers and shelters her, the unfun begins.

In fact, it begins even sooner, with the opening sequence in which writer-director Leonard Stern bends over backwards identifying Burns as the most adorably eccentric geezer you'd ever want to see. In a textbook example of cute-cuter-cutest, Burns is depicted slumbering beatifically, then awakening to an alarm that activates recorded applause, then rising to warm up for the day with a quick softshoe, then kissing his own framed photo, then fixing breakfast for himself and writing a grocery list in an even more dealry humorous way, breaking so many pencils that the last item on the list becomes . . . well, 'nuff said.

The audience is prepared for funny business of an intolerably smirky, cloying sort. Stern, who evidently spent too many years in television before making this belated, inept movie debut, doesn't even trust his cliches to play on their own overfamiliar merits.

Stern transports Burns to a grocery store where a stock boy and female checker proceed to exchange worshipful remarks: "Ah, here comes Old Bill!" gushes one. "I wonder what he's gonna pull on us today?" the other eagerly responds. "Bill is a great way to start the day!" attests Admirer No. 1.

As a result of this smarmy approach, one has pretty much had it up to there with darling old Bill by the time he crosses paths with the runaway, who had been obliged to run away in the nude. It doesn't take much exposure before you've had it with Brooke Shields' character too. Introduced as a precociously fast number, she is quickly plea-bargained down to a misunderstood kid, fundamentally innocent in mind and body and requiring only the right sort of foster home to make her indistinguishable from the typical suburban adolescent on TV sitcoms.

Stern evidently presumes an audience as susceptible as Old Bill's admirers at the supermarket. The plight and reformation of the naked little runaway are equally incredible, flimsy pretexts for musty jokes and psychobabbly uplift. A busy Mr. Fixit, Burns gets to rescue not only Shields but a despondent old crony played by Burl Ives, whom he brings around with the following eloquent outburst: "Damn it, Max, you can walk away from me, but you can't walk away from yourself! Get a grip on yourself so I can get a grip on myself!"

Burns and shields never establish the slightest rapport, but given Stern's deadly lines and inert direction, they never stand a chance. In a typically enchanting exchange, the youngster asks the oldster, "How do I know you're not some kind of pervert?" and he replies, "If I were, I'd have cards printed."

Couldn't someone have informed Stern that a movie camera can show things? At one point he sticks por Shields with the following stagebound observation: "Did you see that? A car's pulling up in front of your house." Similarly, Burns' worried butinski daughter, Lorraine Gary, is obliged to inform Nicolas Coster, who plays her husband."Harris, you're a photographer . . ." Talk about slick!

George Burns needs to swear off roles that reek with cute quirks and sanctimonious speeches. "Oh, God!" was presumptuous enough. His Old Bill is an insufferably counterfeit charmer. And as for Brooke Shields, having outgrown the pre-teen beauty and erotic precocity that made her so fascinating in "Pretty Baby," she would be well advised to devote the next several years to serious study, letting puberty run its course while she learns how to protect herself from directors. CAPTION: Picture, George Burns and Brooke Shields in "Just You and Me, Kid"