Ok, it seems isteve never actually uploaded a fixed version of the level, or maybe he didn't fix everything.
Either way, the problem with the out-of-bounds steel area remained, despite the fact that isteve
talked about figuring out the problem a while back.
Well, now that LemEdit2 more or less works for most people, go make the fix yourself. Open up the level, find the leftmost steel area at the bottom. You'll find that it has a vertical height of 64, which means at the position it's at, it extends past the level's bottom boundary by some 56 pixels or so. Change the vertical height to 8 and save, and you'll be fine, I tested it.