Browser hang up on windows.opener refresh... Why?

I am opening a popup with window.open(...). In the popup there a several pages shown and on one of the pages I am calling the code shown below.

In the most cases the refresh of the opener works perfectly but there are some users which experience problems with this script. The browser seems to be reloading and shows a clean white page with mouse cursor changing to wait cursor. But nothing more happens. The browser is not responding anymore and has to be shut down.

This happens sometimes in IE 7 and 8 and also some users of FF seem to have this problem.

Personally I never experienced this behaviour and I can not reproduce this.

1:
2:
3:
4:
5:
6:
7:

<script language="javascript" type="text/javascript">
	<!--
	if (window.opener) {
		window.opener.top.location.reload();
	}
	//-->
	</script>