Linux – Error installing VSFTPd 3.0.2 on Ubuntu 12.04

I'm following the official documentation to install the 3.0.2 version of VSFTPd.

Commands.

$ wget https://security.appspot.com/downloads/vsftpd-3.0.2.tar.gz
$ tar xvfz vsftpd-3.0.2.tar.gz
$ cd vsftpd-3.0.2/
$ make
$ mkdir /usr/share/empty/
$ mkdir /var/ftp/
$ useradd -d /var/ftp ftp
$ chown root.root /var/ftp
$ chmod og-w /var/ftp
$ cp vsftpd /usr/local/sbin/vsftpd
$ cp vsftpd.conf.5 /usr/local/man/man5
$ cp vsftpd.8 /usr/local/man/man8
$ make install

And I get this error after make install:

if [ -x /usr/local/sbin ]; then \
    install -m 755 vsftpd /usr/local/sbin/vsftpd; \
else \
    install -m 755 vsftpd /usr/sbin/vsftpd; fi
if [ -x /usr/local/man ]; then \
        install -m 644 vsftpd.8 /usr/local/man/man8/vsftpd.8; \
        install -m 644 vsftpd.conf.5 /usr/local/man/man5/vsftpd.conf.5; \
elif [ -x /usr/share/man ]; then \
        install -m 644 vsftpd.8 /usr/share/man/man8/vsftpd.8; \
        install -m 644 vsftpd.conf.5 /usr/share/man/man5/vsftpd.conf.5; \
else \
        install -m 644 vsftpd.8 /usr/man/man8/vsftpd.8; \
        install -m 644 vsftpd.conf.5 /usr/man/man5/vsftpd.conf.5; fi
install: accessing `/usr/local/man/man8/vsftpd.8': Not a directory
install: accessing `/usr/local/man/man5/vsftpd.conf.5': Not a directory
make: *** [install] Error 1

Can anyone help me to fix it?