If you are a for sale by owner the post is not allowed, you can however try blogging about the property; if and when you do list with an agent, he/she can post it for you, ask; or consider any flat fee realty company that feeds into the site.
I tried to do the same and Im a licensed RELATOR and it would not let me. In fact I had to give my phone which led to another REALTOR call me about it without disclosing that to me. As a consumer, I would claim about that deception! I would! Trulia wants agents to buy their service to gain leads generated by the supposed free offering of a listing - probably a minor computer glich- wink wink
sounds like you are trying to list your home on Trulia by owner . the website is what your website is truly is really designed for professionals . you need to call the truly a customer service for help . however I would think long and hard about being a For Sale By Owner . read up on blogs about the pros and cons the biggest con is there are a lot of rules and regulations in home sales and if you are not a professional you could be opening yourself up to a potential lawsuit because you don't know what not to do or what to do . plus you don't get the benefit of the exposure a professional can give your home. it is much more than just throwing something on the internet and hoping a buyer will see it .