The SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP) is a network protocol that provides file access, file transfer, and file management functionalities see wikipedia.
The LibreOffice 4.0.2 has same problem with SFTP.
If you want to upload over internet using Web Wizzard the only way is FTP.
And just the FTP without SFTP.
This can be one of the problem, because many admins working with SFTP.