NWN expansion disk problem

Hi, I just bought Neverwinter Nights Deluxe Edition, which is the original plus the two official expansions: the original on three disks in one box; the expansions each on one CD, together in one box. I give these details because they may be relevant when you hear the problem. I can install it all without any problem. When I try to play the base version before adding exp's, no problem. But when I add Shadows of Undrentide, when I try to play it, it asks for "SoU Play disk." There is of course only one SoU disk, and that it already in the CD drive, so I try Retry. No luck. So I try the original NWN play disk, doesn't work either. So I tried installing HotU, and exactly the same thing happened, it asks for the "HotU Play disk." So I'm either missing a disk (or two) or, more likely I think, it's failing to recognise the disks it's supposed to be registering.
So, any ideas? If this has happened to me, on a new system and with a fresh install without any mucking around, I think it must surely have happened to some other people. I could of course search for a no-CD crack, but I'd rather find a legitimate solution. That being said, if anyone happens to know where I can find a crack, and there are no better ideas, please let me know (I won't really feel bad about the illegality of the crack when I have bought the games legally).
Thanks