ABR11 Bootable Media - Can not backup to USB External Drive

Have tried using the bootable CD to create a backup of my system to an external USB device. Tried two different PCs and two different external USB drives.

If I try to create a folder to make the backup in or to run a backup I get:

Failed to obtain the list of location permissions.
Code: 262,156(0x4000C)
The file is read-only.
Code: 65,521
Read-Only file system.

I can boot into Windows and create files/folders on the backup drive w/o issue.