Have a look at my solution to another issue - [url]http://fogproject.org/forum/threads/fog-server-fatal-error-failed-to-mount-nfs-volume.115/#post-3647[/url]
In short, with a share on openfiler the NFS path was mildly different to the path on the FTP share, that meant that although my NFS share was /mnt/raid6/data/FOG the ftp path was published as /raid6/data/FOG. A couple of edits within FOG and all was well again.