Errors generated when trying to "Backup" with SBSE v6.0.12.0

Hi Lads,

So you get a brief understanding of our backup structure:
Clients: SBSE (Licensed) FTP to our Backup Server
Backup Server: Filezilla Server with FTP accounts configured

We have about 15 clients we do off-site for using this method (note they are small businesses so we don't need to go all-out on an overtly expensive solution).

1 client in particular we've been experiencing a large volume of errors.
* Files upload as 1KB in size before they drop.
* Constant errors with SBSE____.ZZL

Failed to copy from Source : Expected another server reply(15) : 426 Data connection closed. Error scanning content


R:200 Type set to I
L:PASV
R:227 Entering Passive Mode (XX,XXX,XXX,XXX,230,101)
I:Opening data connection to XX.XXX.XXX.XXX Port: 58981
L:STOR C_VOL-b001-i733.md5
R:150 Connection accepted
I:55 bytes transferred. (1.05 KB/s) (51 ms)
R:426 Data connection closed. Error scanning content

Error 2:

Failed to copy from Source : Expected another server reply(15) : 550 Operation not permitted. (Seeking not permitted)


L:STOR SBSE____.YFC
R:550 Operation not permitted. (Seeking not permitted)
L:DELE SBSE____.YFC
R:550 File not found
L:TYPE I
R:200 Type set to I
L:SIZE SBSE____.YFC
R:550 File not found

Can anyone help? This is driving me bananas trying to figure out.

* Rebuilt SBSE Profile from scratch
* Rebuilt Filezilla user account
* Created new FTP account and pointed to a totally different location
* This does not affect any other customer we use SBSE for.

Any help would be appreciated?