IE error with calendar script and FCKToolbar

In IE, FCK works until you invoke a different javascript function(in this case a calendar function) through an onClick event, then the formatting buttons in FCK do not work. Specifically, Javascript returns "this.FCKToolbarButton" is null or not an object". The error is point to the following snippet of code, located in fckeditor/editor/js/fckeditorcode_ie_2.js:
<pre>
function FCKToolbarButton_OnClick(e)
{
this.FCKToolbarButton.Click(e);
return false;
};
</pre>
Really can't figure out what is happening, unless the calendar script is destroying the object somehow. However, I have looked at that code and nothing stands out. But bear in mind that JS is not my forte.

This DOES NOT occur in Firefox.

Any thoughts, comments. advice are appreciated.

Thanks,
Matt