If you encounter this errormessage after a recent update or fresh install with vsftpd 2.3.5 or newer, here is whats happend:
As of vsftpd 2.3.5, the chroot directory that users are locked to must not be writable. This is in order to prevent a security vulnerabilty.
Depending on the configuration you utilize this can be a problem. If so I suggest for the moment to downgrade to 2.3.4 (I’m aware not the best solution!), or change your setup. People with ArchLinux have another solution to this, they can install vsftpd-ext via AUR and then set in the config allow_writable_root=YES. If someone has the patch agains the source for this, I would love to get a copy.
Downloadlinks for 2.3.4
As soon I find a better solution to this problem, I will write again.