wrap not working for me in IE8

wrap not working for me in IE8

I have a jQuery statement which worked fine on IE7 and works on FF, but is failing on IE8.

The line is:
ScratchIFrame().find("fullwordmatch").wrap("<nonmarkupmatch></nonmarkupmatch>");


I added the following before it:

alert(ScratchIFrame().find("fullwordmatch").length);
alert(ScratchIFrame().html());


and get the results:

1
<fullwordmatch>test</fullwordmatch>

the error occurring is:

Message: Unexpected call to method or property access.
Line: 12
Char: 2305
Code: 0
URI: http://ajax.googleapis.com/ajax/libs/jq ... ery.min.js

Does anyone know what the problem might be?

Thanks,
Andy