You can only start a topic in the Top 40 category only if the song has reached the top 100 of the chart, OR if it has an adds date.

When you start a topic, you must do this:

Post its adds date OR post where it is currently on the chart. If it's below #100 on the chart, you must also post the adds date or the thread will get locked.

If the song has been released, then you must post a video of the song. If the song has not yet been released, then of course you won't be able to, so the thread won't be locked.