AutoCAD 2004 Group Policy installation problem

Hi,

We're having problems on all of our existing computers as we attempt to
install AutoCAD 2004 via Group Policy.

I've downloaded the new patch to allow AutoCAD to be assigned to a computer
for the installation and it works fine on a newly installed computer
(running either Windows 2000 or XP). When we come to apply the installation
to an existing computer however, the installation fails with the error:

MsiInstaller Event 11606:
Product: AutoCAD 2004 - Error 1606. Could not access network location
Autodesk\AutoCAD 2004\R16.0\enu\

The existing computers are running AutoCAD 2002 among other programs but
un-installing this does not fix the problem. At the moment the only way I
can get AutoCAD 2004 to deploy via Group Policy is to completely re-install
each client.

Does anyone know how we can fix this error?

Ross