Seems to be some confusion here. I (and Tacit) both read the Dakota's post as saying that there is 117 GB available on the drive and that 58MB is used - not that there is only 58MB AVAILABLE. As Tacit points out, the disk directory, created when you reformat the disk, does take a little bit of space (in this case, it appears to be 58 MB).
So...unless Dakota meant that there was only 58MB free space, there is nothing apparently wrong with the formatting and SuperDuper should be able to back up to this disk IF and ONLY IF this disk is larger than the partition or drive from which the backup is being made.
Any further news, Dakota??