I haven't checked the duplicate content issues but I had a problem recently when I changed server (US to US).

Many of my scripts didn't work on the new server because it was php version 5 not 4 and I had a lot of broken, error pages. There were some other problems because some of the files didn't transfer successfully by ftp so I had a few 404 error pages. Another problem I had was the new server needed an htaccess in key folders, so instead of serving up a landing page on /blue-widgets/ I was serving up an Apache directory listing.

I should have been more careful and at least ran a link checker, such as Xenu.

Cheers,
Paz.

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