"Please add LONG name space to restore"

[steve544c]

I'm trying to restore an older copy of our GroupWise Post Office
(into a Restore location), so we can restore a deleted account,
but I'm getting the above error message on my ARCserve Manager
Job Log.

The Volume already has LONG name space listed on its
mounted volume.

I've tried reverting to two earlier Manager versions, but I'm still
getting the same error. [So far, we've tried ARCserve Manager
12.1, 11.5/SP4, 11.1/SP3.]

Many thanks to any assistance on this matter,

-Steve