What does this mean? What do I need to do? The site in question is:
http://operationlamb.googlepages.com/

On Sun, Jun 28, 2009 at 4:01 AM, Google Sites Team <sites-

Dear Google Page Creator User,
As was previously announced, Google will soon be discontinuing
operation of the Google Page Creator product. We will be migrating
your Page Creator sites over to Google Sites so that they continue to
operate with no work on your part. However, we've identified you as
using Google Page Creator to host files that Sites doesn't support. We
are writing to inform you that, as part of this migration, if you take
no action to address this, your hosted files will likely break. If
they are important then we suggest you move them to a different
hosting service.
Contrary to what was posted in the blog post, the shut down and
migration of Google Page Creator has been extended and will begin in a
few weeks.
Thank you for your patience during this migration.
Sincerely,
The Google Sites Team
Google, Inc.
1600 Amphitheatre Parkway
Mountain View, CA 94043
You've received this mandatory service announcement email to update
you about important changes to your Google Page Creator account.

On Jun 29, 12:15 pm, SDT wrote:

Off hand - your site does not seem to be using a standard Google Pages
theme and the theme you are using is not remotely close to the themes
Google Sites offers. Thus it's likely none of the site files will
migrate as they use custom CSS.

As Google is not giving good feedback on how this migration will work,
or not work, I'd rebuild the site manually and then opt out of
automatic migration. The other option is to allow migration to occur
and then to fix the things that did not migrate.

It's really unfortunate the e-mail does not say which file(s) are at
fault and perhaps what in a file is at fault.  They have said

1) Some file types are not supported on Sites.  See
http://www.google.com/support/sites/bin/answer.py?hl=en&answer=153986
for a list of unsupported file types and then look at the list of
uploaded files to see if any of them are banned.

2) Many other things are not supported. See
http://www.google.com/support/sites/bin/answer.py?answer=144030&topic...
Unfortunately, many parts of this document are vague.

I get the impression that if you ever used HTML mode to edit your
pages then you likely did something that will cause the page to not be
migrated.

Marc