WordPress2.9.1においてpingが送信されない

WordPress2.9.1においてpingが送信されないようです。
サーバーはXreaの有料プランを使っています。

cbnet Ping Optimizer 2.3.1を使ってみたところ、
半分以上にエラーが起きてました。
色々とやってみましたが、うまくpingを遅れません。
解決の糸口を教えて下さい。

» http://api.moreover.com/ping could not be pinged. Error message: “parse error. not well formed”
» http://blo.gs/ping.php could not be pinged. Error message: “parse error. not well formed”
» http://blogbot.dk/io/xml-rpc.php could not be pinged. Error message: “transport error – HTTP status code was not 200”
» http://blogdigger.com/ could not be pinged. Error message: “transport error – HTTP status code was not 200”
» http://ping.qumana.com could not be pinged. Error message: “Incorrect parameters passed to method: No method signature matches number of parameters”
» http://www.bitacoles.net/ping.php could not be pinged. Error message: “transport error – HTTP status code was not 200”
» http://www.a2b.cc/setloc/bp.a2b could not be pinged. Error message: “parse error. not well formed”
» http://www.blogsnow.com/ping could not be pinged. Error message: “parse error. not well formed”
» http://www.rubhub.com/ could not be pinged. Error message: “transport error – HTTP status code was not 200”
» http://www.newsgator.com/ could not be pinged. Error message: “parse error. not well formed”