Snapshot "Failed to MKDIR:" error

Hi folks,

I use snapshot on a couple of my sites, it works beautifully on some but fails on my most recent VPS, with this error in the log:

2013-09-26 06:40:22: Using sFTP connection
2013-09-26 06:40:22: Connecting to host: Port: 22 Timeout: 90
2013-09-26 06:40:22: Login success.
2013-09-26 06:40:22: Home/Root: /vol/shelf1/good/b460894/
2013-09-26 06:40:22: Changing Directory: /vol/shelf1/good/b460894/
2013-09-26 06:40:22: sFTP: Failed to MKDIR: /vol/shelf1/good/b460894/

I have the exact same configuration working on a different VPS, so I can only think that this is down to some version problem or other? (The one that is failing is the latest version of Snapshot ( and a pretty brand new vps also (here is the server info from the snapshot dashboard):

The following table shows version information about your server. When contacting support it might be helpful to provide this information along with your specific issues.

WordPress Version 3.6.1
PHP Version 5.4.4-14+deb7u4
MySQL Version 5.5.31
Is Multisite No
WP_CRON Snapshot uses WP_CRON to run automated backups. If you have disabled WP_CRON via your wp-config.php you will not be able to schedule snapshots.
WP_CRON Enabled.
WP_CRON Lock timeout: 60
_SESSION Snapshot uses _SESSIONS to store temporary information about database tables and files during the backup and restore processing. Sessions are a default part of PHP.
Session save path: /var/lib/php5
Session save path is a valid directory.
Session save path is writeable.
Folder Permissions Writable (0775) – /wp-content/uploads/snapshots
Writable (0775) – /wp-content/uploads/snapshots/_backup
Writable (0775) – /wp-content/uploads/snapshots/_locks
Writable (0775) – /wp-content/uploads/snapshots/_logs
Writable (0775) – /wp-content/uploads/snapshots/_restore
OpenSSL The OpenSSL Apache module is require to make secure connections with destinations like Dropbox and Amazon AWS.
OpenSSL installed
cURL cURL is used when connecting to remote destinations like Dropbox and Amazon AWS.
cURL installed
Version: 7.26.0
SSL Version: OpenSSL/1.0.1e
Libz Version: 1.2.7
Protocols: dict, file, ftp, ftps, gopher, http, https, imap, imaps, ldap, pop3, pop3s, rtmp, rtsp, scp, sftp, smtp, smtps, telnet, tftp
PHP runtime information
Display Errors Off
Error Reporting 4437 - E_ERROR, E_WARNING
Magic Quotes Off
Max Execution Time (seconds) 43200 The value displayed can be adjusted by Snapshot PHP scripts.
Memory Limit 40M - WP_MEMORY_LIMIT defined by WordPress wp-config.php.
Open Basedir Off
Safe Mode Off
ZLib Compression Off

Any suggestions most welcome!