You will need to know a little bit about the environment the site is hosted on.
Doing a directory listing using FTP will give you the permissions of the files in the directory. In some badly set up environments the files you upload may be owned by your user id, however the web server may be running as a different user id, meaning that the web server may not be able to open the files.
You can fix this by making the files readable by all users, to do this using FTP you can use the "CHMOD" ftp command.
Assuming your host is unix (sorry, I don't know anything about Windows, and your host is more likely to be unix). Permissions will look like:
-rwx------
ignore the first - for the moment, the next 9 are three sets of three. The first 3 for the userid who owns the file, the second for the groupid that owns the file, the third set is for the rest of the world. You'll probably want to make sure the rest of the world has read access, you can do this with the command:
CHMOD o+r
If the listing is a directory it will start with a "d" in the first space, in this case you will need to do a:
CHMOD o+x
as well on the directories, as under UNIX directories need "execute" permissions in order to open the contents of.
You can find a little bit of info in the Codex at:
http://codex.wordpress.org/Changing_File_Permissions
A really good guide to FTP clients and some detailed info on file permissions can be found at:
http://www.interspire.com/content/articles/12/1/FTP-and-Understanding-File-Permissions
johnfolsom
ju1ie
travellingfool
Antigone