Discribe does not recognize the volume that I would like to write from.
Upgrade your Discribe to the latest version. Discribe 1.05 will not allow you to write from any volume that is bigger than the size of a CD (650mb). In order for Discribe to recognize your writing volume you will need to partition it to 650mb or less.
Contact CharisMac to get an update to the latest version. Versions newer than 2.0 will allow you to not copy the free space of the hard drive and allows for on-the-fly disc optimization. You can now burn from a 1 GIG drive with 600MB of noncontiguous data. Do not use Norton's Speed Disk to defragment the drive, it does not update the directory of the disk. We recommend highlighting the drive and using the Erase Disk command under the Special pull-down menu. This will clean the disk off, now you can write the files back to the drive, folder by folder, to write it as contiguously as possible.