I hope you spoke with D'Soto's ghost long enough at Shur. Castle after defeating Haleabus, because he tells you the sacred word. After that it should be present in the list.
I don't know if this works, but you might try to find any other creature, select talk and type in Elseramavin. Perhaps then it will register as a word known to you and will be in the list.
You know it has succeeded when Erathmedor starts talking about it already being 100 years ago that D'Soto was there.
If you decide to leave the area and try something different first: I hope you have a save file from before you gave the shroud to him. I'm not sure the game still remembers that you already gave it when you come back after leaving.

i cant get the dragon to open the door, I have given him the shroud and said the secret word "elseramavin" but he wont open the doors he keeps asking for a sacred word
every time i say Elseramavin all he says is "the MAvin sword , The blade forged of twin metals" and thats it but he doesnt open the door.

There are 2 doors in the room with the dragon - not counting the way you came in. THe giant dragonsized door and the smaller door which leads to the Mavin sword. The door to the mavin should be sort of behind you as you speak to the dragon - could you have missed that it is open?
Now - are you typing in Elseramavin or choosing it out of the talk keywords list? Some folks have said he will only acknowledge you properly if you choose the word from the keyword list. Keep trying it.

Also - when you pick up the mavin - let the narration finish before you go on to opening the chests in that room.

Hope that will solve your problem!

Wyv

I check both doors are still closed . the secret word is not in my list of things to say. what did i miss?

I tried talking to the blind guy about "elseramavin" and he says to talk to the dragon, I also have the heard the dragon say the thing about 100 years, but he still wont open the door!!!!

I LOADED A GAME BEFORE I WENT IN TO THE CAVE. I WENT BACK TO THE CASTLE AND TALKED TO DO'SOTA AND HE TOLD ME THE SECRET WORD. WHAT A PISS OFF!! THAT SHOUNT BE ABLE TO HAPPEN. i GUESS I HAVE TO DO THE HOLE CAVE AGAIN GRRRR