I have found all the keys I can and can't open the blue door to his roomDo you mean blue as in tinted slightly blue, or solid blue? I couldn't recall it being particularly blue in D2:ED so checked the DKS walkthrough on Youtube,
part 30 (entering the tower about 5 minutes in). I tried part 25 first, which starts off with giving the book to the Maxos temple librarian.
Do you get a 'can not be opened with Lockpick' type message trying to open the door?
If your door is noticeably more blue than
this screenshot (24KB, PC version), maybe there is a missing texture, or something. If clearing your cache doesn't help, try uninstalling the game off the hard drive (not sure if that effects the saves) and then either reinstall it or try playing off the DVD temporarily.
Try emailing support@larian.com, with a description of the problem and maybe a link to this topic.