Recently, I decided to create a new Knoppix USB key to use for debugging, but in the process of updating various packages, I somehow created a file which is listed as having zero links. Because of the file's (non)existence, Synaptic/dpkg can't replace it or delete it, and won't allow any more updates until I do. I've tried deleting it at a command prompt, I've tried linking it to another name, but every approach I try causes complaints either that it doesn't exist, or that it already exists. I think running fsck would fix it, but these files apparently aren't stored in an actual *nix filesystem, but rather in a file in the USB key's FAT filesystem. How can I mount this pseudo-filesystem from another CD or USB key version of Knoppix to run a fsck on it? I'd really like to avoid starting from scratch and redoing all the configuration that I've already done to this USB key.

[Note that my question has nothing to do with fixing another OS (as many people, including myself, use Knoppix USB keys for); what I'm talking about right now is fixing the Knoppix installation on the USB key itself.]

[Also, if it matters, I used pendrivelinux.com to make this USB key instead of Knoppix's own "copy to USB" scripts, so that I wouldn't have to burn a DVD as an intermediate step, when I'd only need to use the DVD once to create the USB.]