During its initial theatrical engagement in 1940, Walt Disney's revolutionary cartoon feature, Fantasia, had difficulty in attaining financial success because the picture was years ahead of its time, technically and artistically. Recently, though, the film has caught on as new generations have discovered its novel excursion into the world of fine music. Featuring immortal works of composers like Bach, Beethoven and Dukas performed by the Philadelphia Orchestra, Fantasia pioneers a new concept in entertainment. (Now at the Paramount.)