Can't scan to FTP server

My scanner apparently can't save files on the FTP server running on my Raspberry Pi: The server answer, however, seems to consist only of its IP address (printed out when scanning is unsuccessful.
To configure the server, I mostly followed this tutorial(although the server OS is Raspbian 12), except I haven't secured it with SSL, with everything being on my home LAN - and the scanner's FTP client might not support it.
The report printed out is:
Quote:

Scanniong to FTP server failed. Date: Connection error: -4 File put command failed server answer: 192.168.178.4

Here's my vsftpd.conf (I deleted all commented-out lines):
Code:~ $ cat /etc/vsftpd.conf

listen=NO

listen_ipv6=YES

anonymous_enable=NO

local_enable=YES

write_enable=YES

dirmessage_enable=YES

use_localtime=YES

xferlog_enable=YES

connect_from_port_20=YES

chroot_local_user=YES

secure_chroot_dir=/var/run/vsftpd/empty

pam_service_name=vsftpd

rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
rsa_private_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
ssl_enable=NO
user_sub_token=$USER
local_root=/home/$USER/FTP
pasv_min_port=40000
pasv_max_port=50000
userlist_enable=YES
userlist_file=/etc/vsftpd.userlist
userlist_deny=NOOn the server:
Code::~ $ ls -la /home/xeroxb225/FTP
total 16
dr-xr-xr-x 3 nobody nogroup 4096 Dec 9 23:44 .
drwxr-xr-x 3 xeroxb225 xeroxb225 4096 Dec 9 23:32 ..
drwxr-xr-x 2 xeroxb225 xeroxb225 4096 Dec 10 00:47 Scans
-rw-r--r-- 1 root root 17 Dec 9 23:44 test.txtSettings in Scanner's FTP client:
user name: xeroxb225
password:
address: 192.168.178.4:21
file name: /home/xeroxb225/FTP/Scans/scannedimage

where scannedimage is a standard file name, appended with timestamp.

I also tried the server address without specifying the port: 192.168.178.4