maybe, maybe not, I cant say.
when you connect to the FTP server, are you at the same level as the index.php home page?
if not, then yes, that is incorrect.
if you are not at the same level as the index.php home page, then you will need to add the necessary path so that the ftp connection connects to the same level as the home page.
if you website can conect to the MySQL Server, then it should be fine.
The way DW works, is that it puts a file on the server, and uses that file to return information from the data base. This is why the ftp, host directory, and web URL settings are critical.
DW puts a file to the FTP server under <host directory>/_mmServerScripts
then tries to access it using <web url>/_mmServerScripts
so the two must match up.