I redid one of the dorms in one of my games, then saved the dorm (with out anyone in it) to the bin, so I could move it to another family/world and use it there. I got to the university to put the lot down, but it wont let me. its the same lot, the lot says it is a dorm lot (and it is a dorm I am moving) and nothing is obstructing it. am I doing anything wrong?

I don't have an answer for this but can add that I have the same problem with dorms saved to my bin. Hope someone in here has a solution.

nintromon said the magic word: Residential. Thank you!

Here is what I did to be able to place a dorm:
Went in to Edit Town in my regular game
Clicked on the University icon to go into Uni
Went into Edit Town in Uni
Evicted the students
Changed the Lot type to Residential
Saved the Dorm to the bin and went back to the regular game without saving
Went into Edit Town in the game and placed a Residential Lot and was able to put the Dorm from the bin on the lot.

This should work for you if you go back into Uni in Edit Town and change the lot type to residential and save to your bin.