I am not very good with this, but I will give this a shot eh.
I believe the FTP configuration in your zencart admin is not the FTP username that you set with your host; this FTP username is what you should already set in googlebase merchant (go login to your googlebase, settings=>FTP. You will get to configure the FTP username and password.
With this information, input the exact same value into your zencart config for google feed.
FYI, I haven't been able to upload the content up to the googlebase via my zencart even though the login is successful. I upload the file manually. (refer to earlier post on this)
Hope this helps.




