It would not be possible to kill the servant, the only NPC's it is possible to fight with in Dungeon Lords are hostile ones. (too bad, I always wanted to pick a fight with Sir Nil in the hall of weapons...)
If the servant is not there, and the door will not open to get to the elevator then you are experiencing an odd glitch. Hopefully you have an earlier save to go back to, before you spoke to Emmindor at all. If you do, you could go back to that and deliver the horn all over again. It would not be that bad, as long as you didn't have to do the whole trial again.
Here is a link to other threads with "Emmindor" in them. Perhaps you may find an answer there.
http://www.gamebanshee.com/forums/se...earchid=963437
Also, as Claudius mentions, it is a good idea to patch your game if you are playing any version
other than 1.4 or the Collector's Edition. Patch info is here:
http://www.gamebanshee.com/dungeonlords/downloads.php