I have an NPC in game who the player is supposed to greet and have a conversation with. The problem with this is that when I have the 'Say Once' box on the GREETING topic checked the NPC does not use the GREETING topic, only the default hello and goodbye topics. If I uncheck the 'Say Once' box he does use the GREETING topic, but every time you talk to him, which is not what is needed either. Any of you dialogue experts out there ever encounter such a problem? What could possibly be causing this?

Are you setting up a script for the dialog?

Maybe thats what your missing. I believe this post could explain the workings to make it do it once.

http://www.gamesas.com/topic/1400856-trigger-message-problem/

No, this is via a Quest, with the topics set up in the Quest. Once the NPC says the GREETING the rest of the dialogue works; it's just that I can't get him to say it just once; he either says it every time or not at all. There must be something funky going on, but for the life of me I cannot think what it might be.

FYI, the NPC's behavior is controlled by packages; which package is active is determined by what stage the quest is on, with a quest variable as the link. The quest is at the proper stage for the initial dialogue and the proper package is active. So what could be causing this?

Hmmm Im not sure , but I think you need to scrap the say once checkbox and attatch a script for the greeting , like it shows on that link to keep track of the times its said , then redirect.

Since you said your other dialog is working fine , why isnt this greeting just in there with it?

Also what is the trigger for the greeting? And does it wait for a response from the player?

The greeting is the first part of the dialogue and not separate from it. The dialogue is triggered by activating the NPC, just like starting a conversation with any other NPC (i.e. this is not a forced greeting).