The Source Theatre Company's new dance version of "Cinderella," which had its official opening at the YWCA's Penney Auditorium last night, turns out to be a mild, maudlin, amateurish entertainment with little to recommend it beyond the benign earnestness of the participants.

The opening night audience, pretty well filling the small hall, gave the performance a warmly enthusiastic welcome, and one can only applaud the Source's effort to generate a home-grown dance fable of modest dimension (it lasts about an hour). But when a staging of "Cinderella" even has problems conveying the familiar story with a tolerable degree of clarity, you know you're in trouble (don't look for too much help from the printed scenario, which diverges from the stage action in some crucial details).

One key example may suffice to illustrate the quandaries. In this telling of the tale, there's no glass slipper (the dancers are all barefoot); it's replaced instead by what the scenario calls a "magic amulet." What one sees, however, is Cinderella being given a necklace that appears to be made of seaweed. Hidden therein is an object (a piece of costume jewelry) so small and so effectively concealed from audience sight that you're never sure what it is, or why it's so important.

There are other departures from tradition, all equally difficult to rationalize. A brief, faint and fuzzy film segment shows us Cinderella in earlier, happier days, with her "real" parents, who are inexplicably in modern dress though the rest of the show is vaguely medieval in costume. The fairy godmother is at times almost as hostile to Cinderella as her wicked stepmother. A newly invented male character, "Cinderella's best friend," further confuses matters; his only evident function is to give dancer Glen Whaley some leaping to do.

The level of the patchwork production is that of a school pageant. Thomas Bramel's monotonously meandering woodwind score, in a sort of neo-Ravel idiom, contains scarcely a hint of drama or character. The choreography by Martha Brim, who's done some fairly decent, small, modern dance pieces, wants much to be a ballet but hasn't a clue how to go about it. It's the same with the costumes (the stepsisters' ball gowns seem to be as much in tatters as Cinderella's rags), the sets and the dim lighting.

Though the dancing is negligible, Karen Burns makes an aptly waif-like Cinderella, and David Furstenau a reasonably princely looking Prince. For all the production's deficiencies, "Cinderella" is "Cinderella" and the performance retains a certain tacky, innocent charm. If you're looking for anything else--an interesting, contemporary reinterpretation of the myth, say--this isn't the place to find it. The production will run Wednesday through Sunday through June 25.