ActionScript 2.0 :: [FMX2004] Setting The Alpha?

I am having trouble setting the alpha of a movie clip (this is a bitmap, if that matters). My code is as follows:

Code:
on (change) {
if (this.getSelectedItem().data == 3) {
set (this._parent.ahouston._alpha,100)}
if (this.getSelectedItem().data <> 3) {
set (this._parent.ahouston._alpha,0)}
}

I don't believe it is a problem with my combobox actionscript, as just putting:

Code:
set (this.ahouston._alpha,100)

in the only frame of the parent movie clip doesn't work either.

EDIT: Now it shows it with 0% alpha, but won't turn to 100%. I was wrong. It is a combobox problem.