darkbrotherhood quest HELP!

[cheapshot2]

on the darkbrotherhood quest "Of Secret And Shadow" you get a letter from Ocheeva. well i was not thinking and i went off to make some money at a mine. and i needed room and i dropped the letter tottally forgetting to read it. and now it wont let me do the quests. i tried getting kicked out and then rejoining. i tryed just going right to lachances sanctum but he is not there. i was wondering if there was any way to be able to do this quest or to get the letter back so i can read it.

thank you,

C.S2

[LordVampyre]

The instructions say not to let anyone see the letter or tell anyone about it.. so if you dropped it might have buggered it for you. Can you start this part of the quest over?