I know this as I had to do it everytime I reinstalled anything knoppix or kanotix. First run modconf to add the imm or ppa module . Goto the scsi drive section, a ways down the list, then to the imm section and enter through this until it says the module is installed. You can also do this with ppa to be safe if it an older computer.

Next, you have to edit the fstab with this exact entry:

/dev/sda4 /mnt/zip vfat defaults,users,rw,noauto,noexec,noatime,umask=000 0 0

After that you have to create the mount point by making the directory.

mkdir /mnt/zip

Now you can create the device and choose the /dev/sda4(/mnt/zip). You should change the ownership to yourself. Now you should be able to mount the drive and check out what is on the disk that is in. This has to be done as root. Do not mount it as root and forget to unmount it when you leave that account because it will not allow you to mount it as user. As long as you do that then the user can mount it right away.

Please post back results.