joedarock:

Have you tried manually doing the FTP through an FTP client? It might be helpful to verify that you can fetch the file manually to help narrow down where the problem could be.

As far as collecting more diagnostic information, you're already telling the FTP object to report debug information. Perhaps you can increase the debug level to get more details.

Have you tried using the Passive option? Some servers/firewalls (I don't recall which) won't perform file transfers except via Passive mode.

...roboticus

When your only tool is a hammer, all problems look like your thumb.