Problem connecting to an Airport Extreme

[Bill Oldroyd <bill oldieshome org uk>]

I am having a problem connecting to an afp: share on an Airport Extreme 
using Nautilus.

I browse the Network, connect to the share and login using userid and 
password.

I can see the files on the share, read them and delete them.

However I cannot copy a file to the share. The copy results in an error 
- kFPMiscErr - which I think is indicating a problem with 
authentication: authentication has already been made. The copied file is 
created but it has 0 bytes.

There is also a second problem in that Nautilus doesn't update the 
display when new files are added to the shared folder.

The Nautilus version is 3.4.2 running on Ubuntu 12.04.
The Airport Extreme version is 7.6.1.

Can anyone help with this problem as it prevent the Airport Extreme Disk 
facility being used as a shared networ drive across my Apple and Linux 
computers ?.