AS3 display object problem using parent

programming flash
1

ERROR:1119: Access of possibly undefined property contact_mc through a reference with static type flash.display:DisplayObjectContainer.
**
I am trying to figure out why I get a 1119 display object error when I use:
parent.contact_mc.alpha = 1; **
Trying to access a movie clip from another movie clip.
When I use:
MovieClip(parent).contact_mc.alpha = 1;
or
MovieClip(root).contact_mc.alpha = 1;
Get no error but my movie clip contact_mc does not appear.

*Strict mode is turned on

Any help or advice would be fantastic.