Hi,
-- is this a remote or local backup ?
-- have you Advanced Open file option activated ?
-- also refer the link
"The Error "Unable to open the item \\servername\filename - skipped" appears when attempting to backup dhcp.mdb, wins.mdb, and winsmtp.mdb."
http://support.veritas.com/docs/278515
Update us on the same and revert for any further Query
Hope this will help you
Thank you
Gauri