UFacebook – Validation errors from http://validator.w3.org/

I get the following errors form http://validator.w3.org/

Any ideas how to resolve these validation errors?

Line 346, Column 334: Element name fb:login-button cannot be represented as XML 1.0.
… onlogin="_wdfb_notifyAndRedirect();">Login with Facebook</f…
Line 346, Column 334: Element fb:login-button not allowed as child of element p in this context. (Suppressing further errors from this subtree.)
… onlogin="_wdfb_notifyAndRedirect();">Login to Kasabian Live with Facebook</f…
Content model for element p:
Phrasing content.