[scponly] sFTP/scponly stopped working

[mephi]

I've had my sFTP server running for a while now, it's setup it's setup with
scponly so a single group of users all have access to a single directory, so
it's working as a classic, but more secure, FTP server.

I'm running Debian stable, and although I have upgraded from Sarge to Etch,
I'm pretty sure that didn't coincide with this error.

My users started complaining of an "error 13" about a week ago, which was
stopping them logging in. They almost exclusively use Winscp.

I've upped the debug level to get more information, and the auth.log shows
the following:

Jun 20 17:28:05 mephi-linux sshd[11987]: Connection from 192.168.0.254 port
1587
Jun 20 17:28:06 mephi-linux sshd[11987]: Accepted keyboard-interactive/pam
for matt123 from 192.168.0.254 port 1587 ssh2
Jun 20 17:28:06 mephi-linux sshd[11990]: (pam_unix) session opened for user
matt123 by (uid=0)
Jun 20 17:28:06 mephi-linux sshd[11990]: subsystem request for sftp
Jun 20 17:28:06 mephi-linux [11991]: chrooted binary in place, will chroot()
Jun 20 17:28:06 mephi-linux [11991]: 3 arguments in total.
Jun 20 17:28:06 mephi-linux [11991]: ^Iarg 0 is scponlyc
Jun 20 17:28:06 mephi-linux [11991]: ^Iarg 1 is -c
Jun 20 17:28:06 mephi-linux [11991]: ^Iarg 2 is /usr/lib/sftp-server
Jun 20 17:28:06 mephi-linux [11991]: opened log at LOG_AUTHPRIV, opts
0x00000009
Jun 20 17:28:06 mephi-linux [11991]: retrieved home directory of
"/share/adellion" for user "matt123"
Jun 20 17:28:06 mephi-linux [11991]: chrooting to dir: "/share/adellion"
Jun 20 17:28:06 mephi-linux [11991]: chdiring to dir: "/"
Jun 20 17:28:06 mephi-linux [11991]: setting uid to 1003
Jun 20 17:28:06 mephi-linux [11991]: processing request:
"/usr/lib/sftp-server"
Jun 20 17:28:06 mephi-linux [11991]: set HOME environment variable to
HOME=/share/adellion (username: matt123(1003), IP/port: 192.168.0.254 1587
22))
Jun 20 17:28:06 mephi-linux [11991]: running: /usr/lib/sftp-server
(username: matt123(1003), IP/port: 192.168.0.254 1587 22)
Jun 20 17:28:06 mephi-linux [11991]: failed: /usr/lib/sftp-server with error
Permission denied(13) (username: matt123(1003), IP/port: 192.168.0.254 1587
22)
Jun 20 17:28:06 mephi-linux sshd[11990]: Connection closed by 192.168.0.254
Jun 20 17:28:06 mephi-linux sshd[11990]: (pam_unix) session closed for user
matt123
Jun 20 17:28:06 mephi-linux sshd[11990]: Closing connection to 192.168.0.254

And now I'm a bit stuck.

Any ideas?

Cheers,

Matt