You don't even need to try level 52 – it doesn't work either.
2 Tulpar, are you sure the map isn't corrupted? Did it work before?

Yes, I remember playing it many times. And about the sectors. I saved it to a 3.5-inch floppy disk a long time ago and then just deleted it from there, but that was a while ago. And recently, I ran a recovery program on that floppy disk, and it found it, along with several other maps (which I also saved there and then deleted). For 4 maps, it said the status was "Cannot be recovered," but for this one, it said "Good, 100% recovery." I recovered it, and now it seems to be corrupted. Oh well, I guess I won't be able to play it anymore... darn.