CUPS doesn't recognise "application/vnd.cups-raw" format

[Adam Nielsen]

Hi all,

I'm setting up a new server and CUPS is refusing to print jobs arriving 
from Samba, with this error:

D [08/Oct/2012:15:01:33 +1000] Print-Job 
client-error-document-format-not-supported: Unsupported format 
'application/vnd.cups-raw'!
E [08/Oct/2012:15:01:33 +1000] Returning IPP 
client-error-document-format-not-supported for Print-Job 
(ipp://localhost/printers/queuename) from localhost

The usual problem seems to be that raw printing hasn't been enabled, but 
this doesn't seem to be the case here - the raw rules seem to take in 
application/octet-stream data and produce application/vnd.cups-raw data, 
but here CUPS is complaining it doesn't know what to do with the 
resulting vnd.cups-raw data.

Does anyone have any ideas what could be wrong?  How would you normally 
prevent vnd.cups-raw data from being recognised?

I'm running CUPS 1.4.4 (latest stable Debian version.)

Many thanks,
Adam.