The better dado blade sets have holes that are very close to the diameter of the arbor so that the don't hang down a tiny bit and make the bottom of the dado less than flat. That close fit means that you have to keep the blade square to the arbor or it locks up. I used to be able to take my old cheap stacked dado off all at once but that will never happen with my better quality set that has to come off one blade at a time.

 

Thanks Tom, I haven't run into this problem before I've had this set 2 years. Maybe I am just being paranoid.

 

You may have had it stock on a thread, on the arbor when you tightened it up.
Always Wiggle them around and turn them before you tighten, to be sure they're not hung up on a thread

 

It is unlikely you have damaged them they would vibrate like heck making the saw want to walk across the floor.Keep at it you'll solve it .They are a tight fit make sure you have them all bunched properly together. Alistair

 

Thanks gents, you know its always the little things that get you. I will make sure next time it is seated properly and it didn't vibrate/wobble so I am feeling better. I appreciate your help, thanks a million.