http://validator.w3.org error with Contact Form 7

when using Contact Form 7 (last version on wp 2.8.4)
i got the validation error:error document type does not allow element “div” here; missing one of “object”, “applet”, “map”, “iframe”, “button”, “ins”, “del” start-tag
<div class=”wpcf7″ id=”wpcf7-f3-p9-o1″>

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http://wordpress.org/extend/plugins/contact-form-7/