User Title shows up as "guest" though it is listed as "Community Participant"
 

Our site uses two user title "levels." 0-29 posts == Community Participant and 30+ posts = Community Member. When an account is created we use custom code to add the record to the user table and we set the field UserTitle - but when a new user posts, the person is listed as guest and there is no link to the person's statistics. I've just watched this again, I've made 3 posts (in one day) and I am listed as guest. My user table record seems to resemble another user who shows up as I want - as Community Participant with a link to his stats.

How can I configure the system to prevent the listing of new accounts as "guest" ?

If you are using custom code and only adding to the user table when a user is created, you are going to have problems like the one you are seeing. There are several tables that need to get a new user row when a user is created. There are articles in the Articles forums about how to use the vB datamanager to create new users and the data manager will create a new row in every table that needs a new row.