embedding a program to dspace

hello, I use simulink to program dspace CP1104. There are two analog inputs. Also, I need the embedded function block to embed my control program to dspace. I have to use a specific sample time to see the signals smoothly. But with this sample time, I couldn't download the program included embedded functiom block and also adc blocks. It gives an error "task overrun: program can not be executed in real time. Aborting RTI build procedure for model" With smaller frequency, there isn't any problem for downloading but not good signals. So, What is the solution for combined function bloack and adc blocks in different sample times? Is there another problem to download? Thank you?