On both my XP Pro and Vista systems, \Device\HarddiskVolumex\ seems to represent the drive (C:\) containing the registry. For example, the Software hive is at C:\Windows\System32\config\SOFTWARE on both systems. On both systems, \Device\HarddiskVolumex\ seems to be defined in the registry only at Key=HKEY_LOCAL_MACHINE\SYSTEM\Setup, Name=SystemPartition …
On Rico's system (apparently XP?), \Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\ seems to represent the drive containing the registry.
For some reason, it appears this string doesn't translate properly so that the hives on Rico's system can be located by Macecraft products.
For whatever it might help, if anything, a comparison of the registry data for the hives on my Vista (black), my XP (green), and Rico's system (red) are shown below.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\hivelist
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\hivelist
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\hivelist
Name=REGISTRY\MACHINE\HARDWARE Data=
Name=REGISTRY\MACHINE\HARDWARE Data=
Name=REGISTRY\MACHINE\HARDWARE Data=
Name=REGISTRY\MACHINE\SAM Data=\Device\HarddiskVolume3\Windows\System32\config\SAM
Name=REGISTRY\MACHINE\SAM Data=\Device\HarddiskVolume1\WINDOWS\system32\config\SAM
Name=REGISTRY\MACHINE\SAM Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\WINDOWS\system32\config\sam
Name=REGISTRY\USER\.DEFAULT Data=\Device\HarddiskVolume3\Windows\System32\config\DEFAULT
Name=REGISTRY\USER\.DEFAULT Data=\Device\HarddiskVolume1\WINDOWS\system32\config\default
Name=REGISTRY\USER\.DEFAULT Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\WINDOWS\system32\config\default
Name=REGISTRY\MACHINE\SYSTEM Data=\Device\HarddiskVolume3\Windows\System32\config\SYSTEM
Name=REGISTRY\MACHINE\SYSTEM Data=\Device\HarddiskVolume1\WINDOWS\system32\config\system
Name=REGISTRY\MACHINE\SYSTEM Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\WINDOWS\system32\config\system
Name=REGISTRY\MACHINE\SOFTWARE Data=\Device\HarddiskVolume3\Windows\System32\config\SOFTWARE
Name=REGISTRY\MACHINE\SOFTWARE Data=\Device\HarddiskVolume1\WINDOWS\system32\config\software
Name=REGISTRY\MACHINE\SOFTWARE Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\WINDOWS\system32\config\software
Name=REGISTRY\MACHINE\SECURITY Data=\Device\HarddiskVolume3\Windows\System32\config\SECURITY
Name=REGISTRY\MACHINE\SECURITY Data=\Device\HarddiskVolume1\WINDOWS\system32\config\SECURITY
Name=REGISTRY\MACHINE\SECURITY Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\WINDOWS\system32\config\security
Name=Registry\User\S-1-5-21-2736614755-4186107725-1336004102-1010_Classes Data=\Device\HarddiskVolume3\Users\Owner\AppData\Local\Microsoft\Windows\UsrClass.dat
Name=REGISTRY\USER\S-1-5-21-3503787427-2573848751-2203751120-1003_Classes Data=\Device\HarddiskVolume1\Documents and Settings\Owner\Local Settings\Application Data\Microsoft\Windows\UsrClass.dat
Name=REGISTRY\USER\S-1-5-21-436374069-2025429265-725345543-1004_Classes Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\Documents and Settings\Rick\Local Settings\Application Data\Microsoft\Windows\UsrClass.dat
Name=Registry\User\S-1-5-21-2736614755-4186107725-1336004102-1010 Data=\Device\HarddiskVolume3\Users\Owner\NTUSER.DAT
Name=REGISTRY\USER\S-1-5-21-3503787427-2573848751-2203751120-1003 Data=\Device\HarddiskVolume1\Documents and Settings\Owner\ntuser.dat
Name=REGISTRY\USER\S-1-5-21-436374069-2025429265-725345543-1004 Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\Documents and Settings\Rick\ntuser.dat
Name=REGISTRY\USER\S-1-5-20 Data=\Device\HarddiskVolume3\Windows\ServiceProfiles\NetworkService\NTUSER.DAT/
Name=REGISTRY\USER\S-1-5-20 Data=\Device\HarddiskVolume1\Documents and Settings\NetworkService\NTUSER.DAT
Name=REGISTRY\USER\S-1-5-20 Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\Documents and Settings\NetworkService\ntuser.dat
Name=REGISTRY\USER\S-1-5-20_Classes Data=\Device\HarddiskVolume1\Documents and Settings\NetworkService\Local Settings\Application Data\Microsoft\Windows\UsrClass.dat
Name=REGISTRY\USER\S-1-5-20_Classes Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\Documents and Settings\NetworkService\Local Settings\Application Data\Microsoft\Windows\UsrClass.dat
Name=REGISTRY\USER\S-1-5-19 Data=\Device\HarddiskVolume3\Windows\ServiceProfiles\LocalService\NTUSER.DAT
Name=REGISTRY\USER\S-1-5-19 Data=\Device\HarddiskVolume1\Documents and Settings\LocalService\NTUSER.DAT
Name=REGISTRY\USER\S-1-5-19 Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\Documents and Settings\LocalService.NT AUTHORITY.001\ntuser.dat
Name=REGISTRY\USER\S-1-5-19_Classes Data=\Device\HarddiskVolume1\Documents and Settings\LocalService\Local Settings\Application Data\Microsoft\Windows\UsrClass.dat
Name=REGISTRY\USER\S-1-5-19_Classes Data=\Device\Harddisk0\DP(1)0x7e00-0x1bf36a0800+1\Documents and Settings\LocalService.NT AUTHORITY.001\Local Settings\Application Data\Microsoft\Windows\UsrClass.dat
Name=REGISTRY\MACHINE\COMPONENTS Data=\Device\HarddiskVolume3\Windows\System32\config\COMPONENTS
Name=registry\machine\Schema Data=\Device\HarddiskVolume3\Windows\System32\SMI\Store\Machine\SCHEMA.DAT