We had the same problem with Donna's machine; hostrocket server with thousands of PHP scripts located throughout her website (not just PhotoPost directories, in *every* directory on her server).
Change your ftp password - we were able to determine that her files were uploaded 4 months ago using FTP.
All the php files should be removed from the data directory; but you should look throughout your website, because if you have the same issue as Donna's they will be everywhere.
Please do not PM me for support or sales questions. Thank you for your understanding.