Change owner of folder on external disk

I use Robocopy to backup music and photos on a external Western Digital 1TB
disk that is on a local network. The backup worked fine in both cases
initially. Now, the backup for music files is failing with :

Robocopy fails with *EXTRA File 1.9 m A Fine Romance-Browne.mp3
2010/02/15 16:56:41 ERROR 5 (0x00000005) Deleting Extra File
\\externaldrive\public\BackUp-Music\recordings\AmbroseNew\A Fine
Romance-Browne.mp3 Access is denied.
This is the command line using UNC addressing:
Robocopy C:\Users\Owner\Music\recordings\
\\externaldrive\public\BackUp-Music\recordings\ /S /COPYT /MIR
/Log:MusicBkupLog.txt

I think the owner of this folder is incorrect - (nobody (Unix User\nobody) -
others are - administrator (EXTERNALDRIVE\admin)
Access is denied when I try to change owner with:
Properties > Security > Advanced > Owner > Edit > Apply

Nor can I change it with DOS CMD run as administrator:
icacls S:\BackUp-Music\Recordings\AmbroseNew /GRANT ADMINISTRATORS:F
Access is denied.
Does someone have a suggestion for me?
Thanks


--
Frank C
Dell Inspiron 530S
Win Vista Ultimate 64 bit SP2
Dell studio laptop
Win Vista Ultimate 64 bit SP2
HP Photosmart D7260