Flash mx framerate HELP!

hey, just need a little help here,

im maken a movie in flash mx, and when i import SWF clips from swift 3d the framerate changes on the one little piece of the movie,
it lookes like the movie is “lagging” if u know what that means, flash cant seem to keep up,
even when i export the movie it still has this “lagging” which it shouldent,
also on the framerate indicator below the timeline it reads 4.6 instead of the usual 12 when the movie playes over the imported SWF clip.
is there anyway i can fix this problem?