ok... it's vsftpd right? what error are you getting, can't connect at all, or cannot login, that's two different things, vsftpd has local_enable set to no by default.
(from manpage : local_enable
Controls whether local logins are permitted or not. If enabled, normal user accounts in /etc/passwd may be used to log in.)
Check your config file and have a look at vsftpd.conf manpage.