We just installed a SQL 2000 instance in a 2 nodes W2003
cluster. The services are running with a domain account
which is local administrator on both nodes. When we start
the setup for the SQL SP3 on the active node, we get to
the remote setup window, where it asks username, pasword,
and domain for the setup on both cluster nodes, we enter
the info about the same domain account we used for the
SQL2K setup, if gets backs saying "The caller is not the
owner of the desired credentials", and won't let us
continue. Any idea ?

for anybody interested in this issue. The problem was
that the account used for the setup was in a different
domain than the server domain