Hello,
Please note that BE v10.0 does not support the Winnt.
You can verify from software compatibility list.
http://seer.support.veritas.com/docs/264484.htm
However, if you want to install the remote agent on Winnt machine we will try to provide you the best support.
-- The Winnt machine on which you are trying to install the remote agent is in the same domain as the Backup Exec server?
-- Does the username you are providing possess the local administrator rights to the target server?
NOTE : If we do not receive your reply within two business days, this post would be marked assumed answered and would be moved to answered questions pool.