well the same thing happened to me, after fighting malistare, i think it has to do with A. porting home, or the most likely B. the lvl doesnt reset
the solution i found is that sense i was playing on my balance, and my grandmaster ice could go to there by walking, all i did was meet my friend there with ice(you can probably do this with anyone who wasnt in the lvl when it was completed) MY character went on the first pad spot, my friend (who was in the original lvl) went in second, sense i wasnt in the first it reset and then i could port to my friend :D
NOTE: This is only a TEP solution till the admin. fix it i hope this helps everyone!
UPDATE:
it seems my fellow wizard that Malistare isn't the only one in on this porting trickery, Kraysys has also caused me and my friend the same problem, if you find a lvl similar to kraysys's or Malistare's please say so in a reply, this way we can help HeadMaster Ambrose put a stop to their sneaky ways :D
Interesting, this is where my problem seems to start as well...at Malistaire. It is the same wizards I played with in Malistaire that I can't port to, they can port to me though.
So you sugest a reset of the level, since they have no problems only me, I would think just my account needs to go through the door to reset. I will try this first.