sir please help me to solve this issue .and tell me the date of submission of assignment.
The error means exactly what it says. You have a fluid domain around your object called the bounding box. The material point which defines if you have an external or internal flow analysis has to be inside the bounding box! So just make sure you can see a dot inside your domain and you are fine!
As an example please have a look at that picture: Material Point inside the bounding box
All the best!