They substituted Jelena for Sandrine.
Read below from the website referenced above:
"Our guests from the Italian Open in Rome will be Mary Pierce and Jelena Dokic...
Thanks for joining our chat with Mary Pierce. We will soon have a chat summary ready for you. Tomorrow, one of the Sanex WTA Tour's new stars will be with us: Jelena Dokic. Follow the chat and post your questions on Wednesday, 15 May at 5.30pm CET (Rome, Paris).
Unfortunately Sandrine Testud who was initially scheduled has two difficult matches to play on Wednesday. We hope to see her at one of our upcoming player chats very soon."