If it has automount, I don't think you need entries in the fstab. Insert a floppy, go to the floppy mount point, and it should be mounted automatically. If not, mount the old fashioned way, at a different directory. You can't mount the way benjithegreat98 told you to unless you have a proper line in the fstab. Do it the long way:
mount -t vfat /dev/fd0 /mnt/a_dir
Or add a line in fstab:
/dev/fd0 /mnt/a_dir vfat defaults,users 0 0
Search the site for more info. This might help for automount:
Edit: Don't forget to create '/mnt/a_dir' first:
Edit2: I think using 'msdos' instead of 'vfat' makes filenames truncated.