Weird NFS-/apt-get - problem

[Jan Tammen <luser@tammen.net>]

Hello,
I have shared a apt-cache directory rw on a server via nfs for the
rest of my network. On one of my boxes I get the following error-message, 
trying to do apt-get install <anypackage>:

E: Could not get lock /mnt/debs/debs/lock - open (13 Permission denied)
E: Unable to lock the download directory

I actually don't understand this as I can read/write the file from that client
and the same thing works from other clients without problems.

ii  apt            0.5.3          Advanced front-end for dpkg
ii  apt-utils      0.5.3          APT utility programs
ii  nfs-common     0.3.2-2        NFS support files common to client and serve

Any hints? tia.