ActionScript 2.0 :: Mask Slides - Variables And Navigation

The plan:
A mask slides across the screen to give the impression of three buttons sliding in. The animation stops. The user clicks on one of the three buttons and the animation resumes while the buttons slide off of the screen. After the buttons slide off of the screen, the animation should go to the appropriate frame for whichever button was hit.

The details:
The buttons have the following script-
on (release) {
set (nav, 2); <-- Button A sets nav to 1, button B to 2, etc.
gotoandPlay("Mask_Exit"); <--Mask_Exit is the frame for the } animation resuming.

The last from of Mask_Exit has the following script-
stop ():
if (nav=3) {
gotoandPlay("Section 3");
} if (nav=2) {
gotoandPlay("Section 2");
} if (nav=1) {
getURL("javascript:Launch('[URL]')");
}

<--- The Javascript refers to a script to open a window of specific size. The script works fine in separate testing.

The problems:
No matter what button is clicked, the animation resumes (Mask_Exit plays to the end). The animation goes straight to Section 2 (chronologically the next frame in the animation) and launches the external page.