Children, send your parents to bed early tonight. We wouldn't want them coming unglued over "Salem's Lot," an overlong but fitfully frightful CBS movie at 9 on Channel 9. This four-hour version of a Stephen King novel -- to conclude next Saturday at 9 -- is a more assured exercise in the art of the hebbie-jeebies that a number of recent theatrical horror movies have been.

It was directed by Tobe Hooper, who gained first fame, or infamy, with "The Texas Chainsaw Massacre," a film repellent as all get-out but undeniably proficient at fraying nerves to the brownout point. The constraints of television force Hopper to forgo gore for subtler forms of mayhem.

And so with a rat here, a barking dog there, pregnant pans and portentous crane shots, Hooper creates and sustains a persuasive, disbelief-suspending atmosphere of chilling perversity. The Paul Monash screenplay makes even the inevitable TV-movie padding tolerable with characterizations and details that contribute some form of credibility to the tale.

"Salem's Lot" is short for "Jerusalem's Lot," a small and fictional Maine town dominated by a house with a nasty reputation. A vampire moves in, his way paved by a custodian who sets up an antique store as a front, and soon the townsfolk are coming down with what a doctor thinks are cases of pernicious anemia. Pernicious, indeed!

Hooper and Monash try to make it more than a series of shocks. Kids will take to the film partly because it is about the secret world of children; it concerns their exploits as well as their fascination with monsters and fear. The movie also has an accurate fix on the nature of big rumors in small towns and the skeletons that insist on coming out of the closet.

The cast is unusually top-heavy for a horror show. James Mason, as the vampire's confidant, is amusingly suave and sinister from his very first line: "Good afternoon, Mr. Crockett." A number of illustrious old-timers also brighten the darkness, including Lew Ayres as Jason Burke, Marie Windsor as Eva Miller, and Elisha Cook himself as an old wino named Weasel.

Cook gets to hang about on porches issuing mock-ominous proclamations like, "Getting war-mer!"

Bonnie Bedelia makes a very attractive and intelligent herioine, but unfortunately the vampire hunter on the premises is the feckless, expressionless and, from outward appearances, soulless David Soul. What passes for acting on television is sometimes a crime: Soul spent so many years mooning around "Starsky and Hutch" that he thinks hanging his head and murmuring passes for a performance. He's the most crucial flaw in the picture.

The vampire himself, who will not appear until the film's second half next week, is no stricken Lothario or literal-minded lady-killer. He is a blue-skinned, bug-eyed, multifanged ghoul, and an apparition devoutly to be feared.

His first victims are children -- which may give some parents pause -- but there is something eerily pretty about the way one child will appear at a window enveloped in smoke to beckon another sleeping child who lies inside. It is not a wholly original conception, but it gives the film a distinctively unsettling edge.

Because this appears to be a costly, classy production (Stirling Silliphant is the executive producer), a theatrical version for distribution abroad has undoubtedly been prepared; an hour could be cut out of the film with no harm done. This version would contain more explicit horrors: Hooper has to repeatedly cut away at precipitous moments to appease the censor. "Salem's Lot" is still, however, more gruesome fun than most TV movies of its ilk.