[Samba] Send error in SETFSUnixInfo = -5

[Raphael Clifford]

I am trying to mount a samba server using

mount -t cifs -o username=x,password=x //foo.com/username /home/lesshaste/work

and I get

 Send error in SETFSUnixInfo = -5
 CIFS VFS: Negotiating Unix capabilities with the server failed.
Consider mounting with the Unix Extensions  disabled, if problems are
found, by specifying the nounix mount option.

If I then mount with nounix I don't seem to be able to overwrite
existing files but strangely I can delete them.  This makes editing a
file very difficult, for example.

Any ideas what is going on? The client is on ubuntu jaunty 9.04.

I have attached a compressed (and slightly anonymised) version of the
logs for the mount operation above.

Raphael