FYI...
There are only 2 NDS objects that ArcServe creates, an AS_BACKUP SERVER object and an AQ6_<ServerName> Queue object.
As for the Arcserve for NetWare Client Agents, it does not touch NDS. Its strictly a Server to Server communication thing via IPX or TCPIP.
"TheLad" is correct on the Directory structure.
We use ArcServeIT v7.0, with a few still running v6.6, across our entire WAN. It has its issues... but once corrected, it works great!
Good Luck!