I constructed a six floored building with 2 zones. One zone for basement as it is underground and the other zone for all above floors. I am getting fatal error as below, I have an important paper due soon, I have been trying to create this building model since 2 months now. I have attached my idf file if you could please go through it. I did enter appropriate boundary condition as ground for basement still I am getting the error. So if you could please help me solve this error. thank You.