Script Error in IE8

In Firefox it is ok

Here additional information:
here is a screenshot of my Internet Explorer Window.
The URL Page is :

http://at.global50plus.com/kalender_intern_com

Skript-Fehler-Informationen:
====================
OS Information: Microsoft Windows XP Personal Service Pack 2 (Build 2600) OS Sprache: de
Browser: Microsoft Internet Explorer 4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 2.0.50727) 0 Web Browser Sprache: de User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 2.0.50727) Cookies aktiviert Java aktiviert
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Skript-Fehler:
//----------------
Zeile: 780
Zeichen: 127
Code: 0
Fehlermeldung: Nicht implementiert

URL: http://at.global50plus.com/sites/default/files/js/js_72c1a39f0152416e365...
//----------------

What is really strange: http://at.global50plus.com/kalender_intern_com is a view I made.
How can the question mark in the toolbar link to this view (on hover) ???

In firefox it links to aktuell# (on hover) - which is a panel I made ... BUT when I click it does not go to akuell# BUT it shows the context help page.

I do not understand at all.

I deactivated

Help Button is in theme files

on settings page and the error is gone