Hi Paul,

First probably check if you can reach that FTP site with other FTP utilities?

If 'yes', as the following step I would trace TCP packets and analyze FTP commands and responses when uploading file from FTP server using that class and any other FTP utility that does the job.

For tracing TCP packets I use EtherDetect, there should be some freeware tools similar to it on the Internet.

Btw :) may be the issue is much simpler :) then just discard my overcomplicated advise.