This means that someone else has claimed you on their return as a dependent. (or claimed whoever is getting that error message) So, if your parents or someone else have claimed you, you will need to go back and edit your information in the My Info tab to edit it and click that someone else can and has claimed you as a dependent on their return.
If no one else can claim you then you will need to double check your social security number is entered correctly. If it is you will need to print and mail your return.