I'm sorry that you didn't receive an answer to your question from Trulia sooner. Are you still experiencing difficulties adding this listing to our site and your account? If so, please provide us with the complete property address and price so we can investigate further and please provide us with some details about the difficulties you are experiencing. You can post that information here or you can access the link below and send it to our Customer Service team.
Thank you for your patience.
I had the same situation with a listing that I just took. What worked for me was to enter the new listing just as I would any listing. When I input the address and info on the first page it gave me an option to claim the listing and continue entering information. Try entering it again, and see if it gives you an option below the first part that says it's already listed to claim the listing, or enter it as a new listing. Hope that works!