Google Plus One script has quit working on WordPress site, now returns red flag

Here's the Google Plus One script I've been using on my WordPress blog:

<g:plusone a href="<?php echo urlencode(get_permalink($post->ID)); ?>"></g:plusone>

Worked fine for site visitors until it didn't. Now it's returning a red Plus One warning button with a bunch of suggestions to correct the 开发者_如何学Pythonerror, none of which apply.

Does anyone have a Plus One script that will work consistently with WordPress? I don't want to use a plugin.

Thanks.

Here's the answer, courtesy of a sympathetic Google employee:

<g:plusone a href="<?php echo get_permalink($post->ID); ?>"></g:plusone>