Vista - EFS on Windows Vista and 2003 Server

I've recently installed Windows Vista Ultimate on my network, in which
domain and file and print services are provided by a Windows 2003 R2 server.
I'm looking to encrypt a number of files on the network using EFS, but I'm
getting errors on attempting to do so. While I can encrypt files on the
local disk without problems either through Windows Explorer or the cipher
command, it works without problems.

However, if I try this on a network share, either through Explorer or
cipher, I receive the following error:

Y:\>cipher /e TestPasswordFile.txt

Encrypting files in Y:\

TestPasswordFile.txt [ERR]
TestPasswordFile.txt: The environment is incorrect.

0 file(s) [or directorie(s)] within 1 directorie(s) were encrypted.

Any ideas, anyone? I've done a search for the error, but I haven't found
anything relevant.

Thanks in advance,

Alistair

What is the filesystem of the Y file share?
For this to work, the filesystem must be NTFS and the server must be a windows 2000 or later server/workstation.

EFS needs alternate data streams.

Nik