Once entered, it may take Google a few minutes to its cache and see the new version of your site, so I recommend waiting about 30 minutes after entering the code before attempting to verify again.

Various WP forums discuss this topic with people offering alternative methods which worked for them.

Some report success with pasting the code into a page or post and then verifying with google. One will say it works in a post, but not a page and vice versa. Or they will tell you that you must leave the page without a parent.

None of these methods worked for me. The results of one attempt:

A. The site verification code provided by Google was made the title of this page.
http://songbook1.wordpress.com/pp/fx/0-new-features/google265165a8303076b4-html-4/.
I didn't give the page a parent when I made the verification attempt. That was changed after the failure notice.

B. The failure notice says:

Verification failed for http://songbook1.wordpress.com (less than a minute ago). Your verification file has the wrong content.

All attempts have the same result. I've tried this method at least ten times.
Blog url: http://songbook1.wordpress.com/