I'm having a little trouble with my first NPC.

I started by creating my own cell, and a link to it through a place near Leyawin. In that cell, I made a doorway to another cell made by me (think of it as a basemant type thing). In that second cell is my NPC and I've followed a tutorial word for word to try and get a topic to become selectable when you talk to her, but the only thing that shows up is Rumours. I can't think what I might be doing wrong, I've added topics to certain NPCs successfully before, but they were in the open world. I'm using both the Oblivion master file and another former esp armour mod as my ESMs.

What could be the problem?

lol atleast you get that mine says "I have no topic" just edit an existing character to your liking you have the rumors checkbox checked for him thats your problem if you dont want rumors
i dont know how to do custom dialogue sorry

When I create a custom topic, I add a condition to it to make sure only the intended NPC can use it if it is specific to them.
THe GetIsID MyNPCHere is useful to ensure only this NPC has this line.

I also have to make sure to addtopic MyNewTopic, or what ever it is named, either to the NPC's script or into the NPC greeting if they have one.
When I failed to do this, my custom dialog did not show up.

I hope this is of help. Make sure to use GetIsID unless you wish ever NPC in the game able to use the topic.

I hope this helps.

I had the same problem, this thread at might be useful to help you, it did me

http://www.invision.tesalliance.org/forums/index.php?/topic/2622-how-do-i-add-a-custom-race-topic/

The usual reasons for not getting the topic are:
1) You didn't do the AddTopic to make it available, because the right piece of script didn't run, or you forgot to put it in the AddTopics box for a prior dialog item.
2) There's a condition on the topic that comes up false. Wrong stage of quest, wrong ID for speaker, whatever. Remember that the conditions on the main tab of the quest are added in to all of these.
3) The quest it's part of wasn't started! Use the console SQV command to check for running state and stage etc.