Windows 2003SP1/Exchange 2003 SP2, NB 5.1 MP5

Trying to restore entire information store to Recovery Group (followed the
docs to the letter)

Error is:
WRN - error writing object: Microsoft Information Store:\First Storage Group\Mailbox
Store
WRN - error writing byte: 0

Have searched in vain on here for similar problem with no resolution

Any ideas anyone?