Jim Henson, founder and executive producer of the organization, first came to national prominence in the 1960's with public television's "Sesame Street" and a company of Muppets that included Big Bird, Oscar the Grouch, and the Cookie Monster. Then, for five years during the 70's, working in association with Britian's ITC, Mr. Henson and company focused on a series of syndicated half-hours called "The Muppet Show," which led to such feature-film spin-offs as "The Great Muppet Caper." Out of this period came the Gentle Kermit the Frog, using Mr. Henson's voice and often described as the producer's alter ego, and the gloriously demanding Miss Piggy, employing the voice of Frank Oz.

The production logistics behind "Fraggle Rock" provide still another example of the resourcefulness of Henson Associates. Public Television does not have the kind of multimillion-dollar budget required for this type of project, and Mr. Henson candidly confesses that he has been considerably less than satisfied with past treatment he has recieved from the commercial networks. "Fraggle Rock," then, has been put together as a Henson Associates/Canadian Broadcasting Corporation production. The cost for 26 episodes will be covered about equally by the CBC and Home Box Office, which in turn, will be getting its first original weekly series. It is no secret that the pay-cable channels are finding it difficult to fill their schedules with theatrical-release films. Other sources of programming must be found. HBO's participation in "Fraggle Rock" could be a harbringer of future production patterns.

On top of this, Henson Associates will be getting hefty sums from European interests, most notably a German organization, and special efforts are being made in the production and dubbing of the programs for foreign audiences. The tentacles of contemporary financing have an increasingly international reach.

In a conversation recently at his elegant East Side townhouse headquarters, Mr. Henson explained that he had gone as far as he wanted to go with the Muppets. A decision was made to strike out in different directions, to search for fresh concepts. "The Dark Crystal" is certainly far removed from the light-hearted theatrical-entertainment setting of "The Muppet Show." The film explores some of the darker regions of fantasy. Physically, the new puppets are clearly related to the Muppets, and even some of the voices, provided by Henson veterans, are disconcertingly familiar. But in terms of themes and overall personality, "Fraggle Rock" is indeed different.

Mr. Henson explained that "Fraggle Rock,"" taped in Toronto, consciously strives for universal appeal. It wants to break down barriers between people the world over. The puppets, with one curious exception, are of no particular race, religion, or creed. They all depend on one another to varying degrees. Each self-contained episode attempts to illustrate some facet of getting along in a seemingly simple but sometimes complicated world. Occasionally, as Mr. Henson concedes, there is too much of a conrtrived moral in the script, but he feels that, as it progresses, the series will begin striking a less preachy tone.

As a matter of fact, with Duncan Kensworthy as the producer, and Jerry Juhl as head writer and creative producer, "Fraggle Rock" gets off to a remarkably winning start. Fraggle Rock itself, taking a cue from the fantasy genre that includes "Alice's Adventures in Wonderland" is approached through a tunnel that is behind a hole in the wall of a house belonging to a gently oddball inventor named Doc. This character, played by Gerry Parkes, is the show's only human. He never sees the little creatures scurrying about his floor. However, his dog Sprocket does see them and is constantly going into howling snits of frustration in his inability to do anything about them.

Behind the Wall, the Fraggles devote a lot of time to singing, playing, and swimming. While obviously bearing no resemblance to human mortals, they represent, with uncanny and delightful accuracy, a broad spectrum of idiosyncratic human traits. There is no identification problem: The key Fraggles are helpful Gobo, insecure Wembley, motherly Mokey, gloomy Boober, and tomboyish Red. On the first episode, Traveling Matt, an elderly gent, decides to go out through the hole in the wall and explore the world beyond Fraggle Rock, the world he sees as as outer space. Matt periodically sends back letters describing his adventures with sidewalk creatures called parking meters and other such exotica. Meanwhile, back home, the Fraggle live with the Doozers, only six inches tall but singlemindedly dedicated to construction work. The Fraggles, in turn, eat their buildings.

Just outside Fraggle Rock, through another tunnel leading to the garden, is the Kingdom of the Gorgs, a lonely family of giants with pretensions to royalty. The only problem is that the Gorgs have no subjects. They nevertheless affect an Elizabethian-type dialect. Finally, just beyond the Gorgs, is the Trash Heap, an all-knowing seer also known simply as Marjory, who rises magnificently from a garbage pit while wielding a lorgnette. She is the one most notable exception, though, to the goal of anonymous universality. What is supposed to be a gypsy accent comes out very Eastern European ("Troubles? What's to worry?") and sounds like somebody's idea of revenge on a Jewish mother-in-law.

The Fraggles sing (courtesy of a nifty original score by Philip Balsam and Dennis Lee), the Doozers keep their tiny noses to the working grindstone, the Gorgs lurch about fearsomely, and Sprocket the dog has all sorts of emotional crises. There are a few kinks in the production, but the mix already works marvelously well. Henson Associates seems to have come up with another winner, this one more geared to young audiences but, like "The Wizard of Oz," accessible to all. Others deserving credit include: Diana Birkenshield, executive in charge of production; Micheal Frith, conceptual designer, and Faz Fazakas, director of electronic-mechanical design. The voices are provided by Jerry Nelson, Dave Goelz, Steve Whitmire, Kathryn Mullen, Karen Prell, and Richard Hunt.