@ERROR: chdir failed but directory exists

I have a D-Link DNS-320 and I've installed FFP and I'm trying to get rsync running on it.

So far I've got the daemon up and running and I've defined a module in my rsyncd.conf like so:

max connections = 10
secrets file = /ffp/etc/rsyncd.secret

use chroot = false
read only = no
list = true
strict modes = false
#hosts deny = *
timeout = 600
dont compress = *.gz *.tgz *.zip *.z *.rpm *.deb *.iso *.bz2 *.tbz *.mkv *.avi *.mpg *.jpg *.rar
pid file = /var/run/rsyncd.pid
reverse lookup = no

[root]
hosts allow = *
read only = false
gid = allaccount
uid = nobody
auth users = greg
path = /mnt/HD/HD_a2/rsync
comment = Fish
list = yes

/mnt/HD/HD_a2 is the internal disk and /mnt/HD/HD_a2/rsync exists:

root@nas:/mnt/HD/HD_a2/rsync# pwd  
/mnt/HD/HD_a2/rsync

with the following permissions:

root@nas:/mnt/HD/HD_a2# ls -la
total 154589
drwxrwxrwx 23 root   root            4096 Oct  2 19:44 .
drwxr-xr-x  3 root   root            1024 Oct  2 17:20 ..
drwxrwxrwx  4 root   root            4096 Dec 29  2013 Ajaxpf
drwxrwxrwx 21 nobody allaccount      4096 Oct  2 15:45 NAS
dr-xr-xr-x  4 root   root            4096 Sep 24 17:45 Public
drwxr-xr-x  3 root   root            4096 Sep 24 17:45 Users
drwxr-xr-x 17 root   root            4096 Aug 27 14:11 ffp
-rw-r--r--  1 root   root            1117 Oct  2 17:20 ffp.log
-rwxr-xr-x  1 root   root            1942 Sep 23 17:29 fun_plug
drwxr-xr-x  2 root   root            4096 Jul 15  2012 logs
drwxrwxrwx  2 nobody allaccount      4096 Oct  2 21:09 rsync

I have the user greg defined in my rsync.secret file and I can successfully connect from my (Windows) client and list the module:

C:\Batch\rsync> rsync greg@nas::  
root            Fish

However; When I try to send a file I get @ERROR: chdir failed:

C:\Batch\rsync> rsync -vvvv SRC test.txt greg@nas::root/test.txt  
opening tcp connection to nas port 873  
Connected to nas (192.168.10.5)  
note: iconv_open("UTF-8", "UTF-8") succeeded.  
sending daemon args: --server -vvvve.Lsf . root/test.txt  
@ERROR: chdir failed  
[sender] _exit_cleanup(code=5, file=/usr/src/ports/rsync/rsync-3.0.9-1/src/rsync-3.0.9/main.c, line=1516): entered  
rsync error: error starting client-server protocol (code 5) at /usr/src/ports/rsync/rsync-3.0.9-1/src/rsync-3.0.9/main.c  
(1516) [sender=3.0.9]  
[sender] _exit_cleanup(code=5, file=/usr/src/ports/rsync/rsync-3.0.9-1/src/rsync-3.0.9/main.c, line=1516): about to call
 exit(5)

I'm using Cygwin rsync version 3.0.9 on the client and rsync version 3.1.0 on the server.

On the server, rsync is running as root:

root@nas:/mnt/HD/HD_a2# ps aux | grep rsync  
root     10074  0.0  0.3   1996   376 ?        Ss   21:57   0:00 /ffp/bin/rsync --daemon --config=/ffp/etc/rsyncd.conf --log-file=/var/log/rsync.log --ipv4 -vvvv

Why is chdir failing?

root can write to /mnt/HD/HD_a2/rsync:

root@nas:/mnt/HD/HD_a2/rsync# touch /mnt/HD/HD_a2/rsync/touch  
root@nas:/mnt/HD/HD_a2/rsync# ls -la  
total 8  
drwxrwxrwx  2 nobody allaccount 4096 Oct  2 22:21 .  
drwxrwxrwx 23 root   root       4096 Oct  2 19:44 ..    
-rw-r--r--  1 root   root          0 Oct  2 22:21 touch  

and rsync is running as root.

There's nothing useful in the log on the server:

2014/10/02 22:19:35 [10391] rsyncd version 3.1.0 starting, listening on port 873  
2014/10/02 22:19:41 [10394] connect from UNDETERMINED (192.168.10.37)  

So why is chdir failing? or how can I diagnose the problem further?

UPDATE #1

Regarding this being a duplicate of Configuring anonymous rsync daemon but the solutions pertained to SELinux being the issue. The DNS-320 runs an embedded, slimmed down version of Linux, which does not include SELinux's getenforce and setenforce commands, so if it is this, as suggested in the comments, how can I rectify it?

As these tools aren't available, what else could it be?