IE8/ Firefox/ Chrome compatibility issue

1) Script Title: Flying Planes Script

2) Script URL (on DD): http://www.dynamicdrive.com/dynamicindex4/plane.htm

3) Describe problem: I have created a home page using this script. It can be seen here http://www.hollisterairshow.com/index.html . It works well using IE8, but the image doesn't move around the screen at all when using Firefox or Chrome, the image just stays in the top left corner of the page.


I'd really appreciate any help on this.

Thanks,

Tony