AS 2 specifiying a button problem (flash-CS3)

might not be able to explain this very well but here goes.
i have an swf file with an empty movieclip in it.

i have set up an XML file that when clicking the next button pulls the next swf from the XML.
this is all working fine. however when i try to specify the next button from one of the sub swfs within the main one i have no luck.

when i do a trace it works but it seems to ignore the code above it…see below.

_parent._parent.nextbtn.onRelease = function(){

i tried deleting the function that is on the nextbutton in the main swf timeline but that doesnt work either. i can always create separate swf files every time i want a new section but i thought i would check out see if there was another way.

sorry if this makes no sence.

any help would be brilliant guys… would upload fla but it drags bits from everywhere out of about 6 differnt folders so not a possibility i am afraid