Netware 6.0 SP4, WinXP SP2, Client 4.91

We have a file with 7,1GB on NSS-Volume. At the client it is shown with
a size of 4GB. We are unable to copy the file. After logging out and a
new login, the correct filesize is shown and copy is possible. After a
restart of the client, the same problem reappears.

Client 4.91SP1 did not help.
Please Help. Thanks.
Ulrich Frei