Permission problem with update option

Hello,
I use a cwrsync 2.0.1 Server and Client on windows 2000.

When I use rsync to archive a directory structure everything works fine.
i.e. the command:

rsync -av /sub/ tom@server.org::backup/sub

does not generate any errors.

However if i try to update the server with

rsync -urv /sub/ tom@server.org::backup/sub

I get a "permission denied" error.

rsync: rename "/cygdrive/e/backup/sub/.data.pst.002368" (in backup) -> "data.pst": Permission denied (13)
I have tried to run the rsync service with a user account with admin privilege, but I get the same error.

Has someone come accross this problem before?

Thanks,

Michael