[Plugin: WP Favorite Posts] Not valid code

Stunning plugin! But…
If we check a web-page with the installed wp-favorite-posts on validator.w3.org, we get error message:

document type does not allow element “ul” here; missing one of “object”, “applet”, “map”, “iframe”, “button”, “ins”, “del” start-tag

<span class=’wpfp-span’>

• Your favorites is empty

<img src=’http:…
The mentioned element is not allowed to appear in the context in which you’ve placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you’ve forgotten to close a previous element.

One possible cause for this message is that you have attempted to put a block-level element (such as “<p>” or “<table>”) inside an inline element (such as ““, “<span>”, or “<font>”).

You should replace “<span class=’wpfp-span’> ***</ span>” on “<div class=’wpfp-span’> ***</ div>”.

http://wordpress.org/extend/plugins/wp-favorite-posts/