I do not use Konqueror.
If one of your points is that it is dangerous to refer to the floppy as /dev/fd0, then that does seem to bugger things often, I agree.
Cannot myself do this experiment - my computers have been seized by US terrorists - but if supermount is the problem then surely switch it of, use mount and umount normally, and see if this resolves the problem.
simple way to turn off supermount
or simply comment out the supermount floppy line in fstab - it can then be reinstated in a moment.
Would it be necessary to add say:
/dev/fd0 /floppy auto user,noauto 0 0 (or /mnt/floppy or whatever)
to /etc/fstab ?
Then test to see if problem persists. And something will have been established.