Flex到远程服务器

I am trying to get a Flex/PHP application set up and am having problems connecting to my server. The database/PHP isn't going to be hosted on a local server, it will be hosted on a remote server along side the PHP. When I am trying to set up the project, I am asked for the web root but when I put in the ftp or URL to the remote server it throws the "The web server document root is not a valid directory". All information I have found seem to be pointing to having a locally hosted version of the server, but that isn't possible. Is there any other way?