Combo Box problem

[query007]

Hi!,
i am creating a registration page on flash and in the form im using a combo
box for secret question...the problem is that how do i get an error to display for when the user doesnt select an option in the drop down combo box....
heres what i have so far.....

if (_parent.SecretQ_cb.selectedItem.label(0))
{
arrayOfErrors_array.push("Secret Question is filled in field");
anError = true;
}
0 is just blank...any help is appreciated!