THE AMERICAN Film Institute's European Community Film Festival, now in its 10th year, opens this weekend with "The Witches," an adaptation of the Roald Dahl book. Directed by British director Nicholas Roeg in collaboration with the late puppeteer Jim Henson, the movie screens at 6:30 and 9 Friday.

The festival concludes June 30 (at 8) with Italian director Mario Monicelli's "The Obscure Illness," a romantic comedy starring Giancarlo Giannini and Emmanuelle Seigner. In between are 26 other films and videos, selected from the 12 European Economic Community member nations.

The most intriguing work is likely to be Chris Marker's "The Owl's Legacy" ("L'Heritage de la Chouette"), a recent 13-part, 5 1/2-hour French television series about Greek culture. The series will be shown on consecutive Mondays and Tuesdays; thus Parts 1-3 will be shown Monday and repeated Tuesday, Parts 4-6 on June 11 and 12, Parts 7-9 on June 18 and 19, and Parts 10-13 on June 25 and 26.

There are other promising possibilities, including German filmmaker Rudolf Thome's Eric Rohmer-like "Trilogy," about modern love relationships in Berlin. The first, "The Microscope," is shown at 6:30 Wednesday (and at 5 on June 10); "The Philosopher" follows at 8:45 Thursday (and at 7 on June 10); the finale "Seven Women" screens June 9 at 6 and June 10 at 8:45.

Jean-Jacques Andrien's "Australia" (June 15 at 8:45; June 16 at 8:15) is about a Belgian war veteran (Jeremy Irons), now living in Australia, who tries to keep the past from his daughter. "Man No Run" (Saturday at 8, Sunday at 4, Tuesday at 6:30), Claire Denis's documentary about the Cameroonian band, Les Te~tes Brule'es, is the French director's follow-up to "Chocolat," her enchanting debut set in Africa.

Highly recommended: "Completely Pogued" (June 20 at 8:45, June 21 at 6:30), Billy Magra's video documentary of the Pogues, the fabulous back-to-basics Irish band. Although this one may just be for Pogues and post-punkers, it's great fun to spend time with this intriguing, spirited collection of talented musicians.

Of particular interest is band leader Shane MacGowan, an endearing, childlike songwriter with one of the worst sets of teeth in rock and roll. Although Pogue friends Joe Strummer, Kirsty McColl, Steve Earle and David Byrne express support for the band's music and attempt to dispel rumors about the band's heavy drinking, their testimony is shattered by MacGowan himself, who admits to regular imbibing. But it's the rousing originality of the songs that come through loud and clear. Great fun.

But stay away from: Chantal Akerman's 1988 "American Stories: Food, Family and Philosophy," (shown at 6 Saturday and 8:45 Tuesday), an unconvincingly staged collection of monologue routines, in which American actors (in wooden character) narrate personal anecdotes "inspired" by the writings of Isaac Bashevis Singer.

Admission to EC festival events, as with all AFI movies, is $6 ($5 AFI members); call 785-4600 for recorded schedule.

ALF Sjoberg's 1944 "Torment" screens at 2:30 Saturday at the National Gallery of Art's East Building, part of a brief Sjoberg-Ingmar Bergman series that concludes July 1. Scripted by Bergman (who also served as assistant director), "Torment" is about the relationship that develops between a student (Alf Kjellin) who's being tormented by his Latin teacher and the shopkeeper (Mai Zetterling) in whom he confides.

Sjoberg's 1951 "Miss Julie," an adaptation of Strindberg's one-act play about the tortured love between a count's daughter and a groom, will be shown at 6 Sunday. Both movies are free.

AS YOU probably know, "Robocop 2" is advancing upon us; it's scheduled to open June 22. Orion Pictures has rereleased for one week the original "Robocop." In the wittily presented original, an automated crime fighter built from a dying cop (Peter Weller) comes back to take care of that Detroit riffraff. "Robocop" will screen at six theaters in the metropolitan area; consult the Movie Guide listings for exact locations.