Loading .swf's

I have swf that I have loaded from the link in a button into a movie clip using the code:

on (release) {

It loads fine and the buttons in the loaded swf work fine, its just when the combo box is selected it freezes and doesnt even drop down its items. Is there any reason for this? and how can I fix this problem?

Apparently it has something to do with “_root” but I can’t figure out how I would change it to make it act like it does when I loaded it up by itself.