There are a couple questions you could have answered wrong under My Info. Click on My Info then click Edit by Dependents, then click Edit by their name and go though all the screens again.
First of all check their date of birth. Also you need to enter a ssn for them. Check the one that says did your CHILD pay more than half of their support. It's not asking if you did.
If you can't get it to change then try completely deleting them and re-entering them. Sometimes that helps to clear something out.
