IE8 JS Error

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; GTB6.3; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.21022; InfoPath.2; .NET CLR 3.5.30729; .NET CLR 3.0.30729)
Timestamp: Wed, 23 Dec 2009 12:24:01 UTC

Message: Invalid argument.
Line: 111
Char: 1539
Code: 0
URI: http://xxx.xxx.com/ckeditor/ckeditor.js

Any ideas?

Editor instantiates once. On second attempt, it fails. Works perfectly in Firefox 3.6.

Code we're using:-

if ( editor )
editor.destroy();

var html = document.getElementById('editor_seg1').value;

// Create a new editor inside the <div id="editor">
editor = CKEDITOR.appendTo('html_editor',
{
toolbar : 'Basic'
}
);
editor.setData( html );