NTDSUTIL / IFM Fails with error 0x80070001

I am using ntdsutil to do a sysvol backup of my domain controller (Windows Server 2008 R2) as follows:

create sysvol full \\fileserver02\onsitebackup\domcontroller01\ifm_01

More Details:

\\fileserver02\onsitebackup\domcontroller01\ifm_01

is a share on my Synology NAS

I am running the command from an elevated command prompt.

Following is what I get

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ifm: create sysvol full \\fileserver02\onsitebackup\domcontroller01\ifm_01
Creating snapshot...
Snapshot set {0f644b60-07d4-4a27-85e9-1fe129c29bd0} generated successfully.
Snapshot {1eb950df-75ef-47ef-a096-2a652756895d} mounted as C:\$SNAP_201504191427
_VOLUMEC$\
Snapshot {1eb950df-75ef-47ef-a096-2a652756895d} is already mounted.
Snapshot {1eb950df-75ef-47ef-a096-2a652756895d} is already mounted.
Initiating DEFRAGMENTATION mode...
     Source Database: C:\$SNAP_201504191427_VOLUMEC$\Windows\NTDS\ntds.dit
     Target Database: \\fileserver02\onsitebackup\domcontroller01\ifm_01\Active
Directory\ntds.dit

                  Defragmentation  Status (% complete)

          0    10   20   30   40   50   60   70   80   90  100
          |----|----|----|----|----|----|----|----|----|----|
          ...................................................

Copying registry files...
Copying \\fileserver02\onsitebackup\domcontroller01\ifm_01\registry\SYSTEM
Copying \\fileserver02\onsitebackup\domcontroller01\ifm_01\registry\SECURITY
Copying SYSVOL...
Copying \\fileserver02\onsitebackup\domcontroller01\ifm_01\SYSVOL
Copying \\fileserver02\onsitebackup\domcontroller01\ifm_01\SYSVOL\mespl.com.sg
Copying \\fileserver02\onsitebackup\domcontroller01\ifm_01\SYSVOL\mespl.com.sg\P
olicies
Copying \\fileserver02\onsitebackup\domcontroller01\ifm_01\SYSVOL\mespl.com.sg\P
olicies\{31B2F340-016D-11D2-945F-00C04FB984F9}
Copying \\fileserver02\onsitebackup\domcontroller01\ifm_01\SYSVOL\mespl.com.sg\P
olicies\{31B2F340-016D-11D2-945F-00C04FB984F9}\GPT.INI
 error 0x1(Incorrect function.)
 error 0x80070001(Incorrect function.)
 error 0x80070001(Incorrect function.)
 error 0x80070001(Incorrect function.)
Snapshot {1eb950df-75ef-47ef-a096-2a652756895d} unmounted.

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Please help. Thanks!

Rgds

Caleb Suresh