Trying to share folder on ubuntu that can be access by a WinXP machine

I have Ubuntu 10.04 installed and I am trying to share a folder on a mounted internal drive that was created with NTFS. I've installed and run the NTFS configuration tool on the drive. When I try to share the folder I get the following message:
'net usershare' returned error 255: net usershare add: cannot share path /media/DRV2_VOL1/Quicken Backup as we are restricted to only sharing directories we own.
Ask the administrator to add the line "usershare owner only = false"
to the [global] section of the smb.conf to allow this.

I have admin rights to my computer. How do make this modification?

Thank you.