The platform on which EthOS is built does not allow an individual to have more than one project with the same title, so you will have to modify your project title in order to get past this error message. If you are submitting multiple REB Application forms for a larger project, you may wish to consider how these might be differentiated, e.g., with a year, subtitle, "Study A".
Note: If you are submitting a Statement of Intent with the same Project Title that you intend to use for your REB Application, please add "SOI:" in front of the project title within your SOI form.