Looks like you moved a lot of the </fieldset>s around, mostly to move them up to just after the </legend> - not sure why you did that as it means the <fieldset> doesn't contain any fields, which defeats its purpose).
Also looks like the recaptch is inside <div class="newsletter_block"> - again not sure if you meant it to be.

I'm amazed that removing an extra </fieldset> would cause the page to crash - malformed html rarely crashes pages, it's usually bad php that does that.

Regards
David