Problem with button in IE

Hi,

I have a button in a website that, when clicked, should go back to the last page visited by the user (in this case, it would go back from “example.com/page” to “example.com”). I’m using this code in a AS2 Flash button:

on (release) { getURL("javascript:history.go(-1)","_self"); }

This code works fine with Mozilla Firefox, but when I click the button in Internet Explorer, it goes back to the last page but it also opens a new window with the same page.

I’ve tried with this code too, but the same thing happens:

on (release) { getURL("example.com", "_self"); }

Does anybody knows how can I solve this problem? I’m really stuck here.
Thank you!