bgiframe plugin causes error in IE9

The uiquery plugin bgiframe (version 2.1.1) causes the following java script error in Internet Explorer 9:

jquery.bgiframe.js, line 94 character 5

My menu does not work any more, I hope the reason is this error.

Any ideas?

ADDED:

The line in jquery.bgiframe.js is:

this.insertBefore( document.createElement(html), this.firstChild );

and the error sais:

SCRIPT5022: DOM Exception: INVALID_CHARACTER_ERR (5)