Using the 'parent' property

Hey, I’m having some problems converting my AS2 code to AS3. I think i’ve pretty much go it all sussed except for this one problem: and i would think it’s a very simple one, but alas…

From inside a symbol, i want to change the location of a MC on the main timeline.

So logically i would think that the code would be:

[COLOR=Blue]parent[/COLOR].my_MC.[COLOR=Blue]y[/COLOR] = 20;

but this gives a compile error of:

[COLOR=Red]1119: Access of possibly undefined property my_MC through a reference with static type flash.display:DisplayObjectContainer.parent.my_MC.y = 20;[/COLOR]

I’m sure i’m missing something obvious, but seeing it’s 5:00pm on Friday arvo my brain has already switched off :ponder:.

Any ideas?