Old as1 project converting to as3, cannot create properties errors

i am taking an old as1 project and converting it into as3

i believe all of my publish settings are correct
there are 2 classes in my library with base class movie clip
menucaller
mysqlurl
menucaller and mysqlurl each have an .as file associated with them, and are exported for actionscript
on the stage i have instances of of menucaller
on mouse over of menucaller, menucaller adds itself a child of mysqlurl via the menucaller.as file
the problem is that sometimes this works perfectly fine,
but sometimes i get errors of “cannot create property” referring to properties of mysqlurl
sometimes copying and pasting all of the layers into a new project corrects this, but sometimes it does not
i have an example of the problem here:
http://yankeescreen.zxq.net/problem.rar
in the folder there are 2 .fla files, one labeled “works” one labeled “dontwork”, self-explanatory

plz help me out, i think youll have to take a look at the files in order to help with this one because ive tried everything and there really seems to be no source of this problem