Dissapearing mc after fade in

When using this script

onClipEvent (load) {
this._alpha = 0;
onClipEvent (enterFrame) {
this._alpha += 10;

my mc dissapears after a seemingly random period of time…

[color=#22229c]Heres[/color] the site im working on.

If you watch the outer border for between 1 and 4 mins (sorry im aware you’re all busy!!) it mysteriously dissapears… cant understand why… any ideas guys?

Thanks in advance