Problem with the quest.

[KK3003]

OK, so i have been playing this masterpiece for some time now, but I am stuck in the quest line. I've recieved a letter, that says I need to go to a residence of Rhogallala(or someone like that) in Sentinel, but i cannot talk about that residence with anybody. Do I need to go and look for it in Sentinel, checking EVERY residence there is? Because it would take ages to do. I don't even know if I am supposed to do that quest, since my journal is bugged(yeah, god damn it buggerfall) I might have already done this quest, I don't even know. Oh, and for the letter itself, It was sent by Suchem, a servant of the Underking. Could someone help me out? I really want to progress in this game

[SarthesArai]

I assume you are refering to that part of the main quest where you have to give the totem of tiber septim to any of the suitable candidates (a lot of quest names and locations are randomly assigned, and all but the main story quests can be repeated infinitely as long as you meet the requirements).
As far as I remember, the location of a target residence can either be asked by the residence's name, or the name of the person you are required to meet there. Just try asking the sentinel people about ALL topics available, and see if any matches.
That's only if you want to give the totem to the underking. You know that there are several endings to the game, and you are at the moment to decide which one it will be, don't you? (At least if I was correct about my guess about the quest you're refering to)

[KK3003]

I don't think it's the totem quest, I've just finished the missing prince and then I recieved that letter. I tried to ask about that Rhogallala, or his mansion, but there is no option like that. I didn't do the Orcish treaty, so it cannot be Who gets the totem quest. I actually just found which quest it is. It's called "Stronghold of the Blades", but is there any way to find that god damn residence, or do I need to check every house there is in that town?

[SarthesArai]

Ah, yes, I see.
Are you sure the agent is to meet you in the city of sentinel, not just the kingdom of sentinel? Take a look at the letter you recieved, its end should read something like "[...] You can find me at (building) of (town) in Sentinel. I will wait one month. [...]". Make sure you look in the right town

[KK3003]

EDIT: I am the dumbest piece of [&@%!] there is, because I couldn't think of Rhogallala as a city. Thank you for your attention kind sir, you helped me fight my own stupitidy!