If you are in Milestone2, the only config file parameters that need to modified in addition to the ones specified in Milestone1 instructions are these:
Note: Do NOT set any other config parameters related to anonymous mode, passive mode, chroot, ftpuser, ftp_username or run_as_launching_user.
Try to understand what these parameters mean by going through the config reference page at http://vsftpd.beasts.org/vsftpd_conf.html
If you are in Milestone3, the config parameters to be modified are specified in the instructions. Do these in addition to what you have done in Milestone2.
NOTE: If these config parameters already exist in the config file, use them to set the values correctly. Only if they are not present, add them to the config file.
If you have added too many things to your config file, start with a clean config file. You can get this from the tar file in the QBox directory or if you have backed up the original config file as instructed.