Scope problem?

This is a situation: i have a index.swf in which i have holder movieclip in which i load gallery.swf (where i load pictures in it’s holder mc). The thing is i used _root in gallery.swf so when i publish it separately it works, but it doesn’t work within index.swf. I suppose there is a scope problem where _root adresses _root timeline of index.swf instead of gallery.swf when index.swf is published and gallery.swf loaded inside. I tried to solve this by putting:

this._lockroot=true;

inside of gallery.swf but now my Flash 8 player just freezes when index.swf is published and gallery.swf loaded into it but i have no idea why? What would be other solution for this problem?

thanks