clipping effect import

hi all - i have a few scenes that i have exported out into a single swf file. am importing the file back in so that i can add continuous streams of background music to it (there are six music files that span the three scenes, so breaking them up into 18 sound files then copy/pasting would be a pain). I import swf files back in for this procedure rather often and never have had an issue … however, in this case, when i attempt to import the swf file, i get an error message that the clipping effect portion cannot be imported … is this normal? is it only with swf files or will mov files react the same way when it comes to clipping effects? i use the clipping effect a lot but have not tried to import one so i just want to know if it’s a problem on my end or a software restriction … thanks, dan