I installed the plugin (copied the files) without a problem but when tried to activate it I received the following error message:
[www.<sitename>.com] [Tue Jan 22 20:05:29 2013] [error] [client 188.8.131.52] Premature end of script headers: plugins.php, referer: http://www.<sitename>.com/wp-admin/update.php?action=install-plugin&plugin=wordpress-seo&_wpnonce=d0f0a17a68
Error 500: Script Execution Failure
Did anyone had the same problem? If so and already solved it, please share the magic.