TLS/SSL FTP Server and Ubuntu 12.04 Filezilla don’t go together

It may seem strange but you cannot use TLS/SSL FTP servers with Filezilla in Ubuntu 12.04.

And that’s just the tip of the iceberg. Actually the problem lies with GnuTLS which Filezilla uses.
So for now just use your FTP client in Windows which statically link GnuTLS.