BSC error in no display mode

Hi,

There is a program that takes an excel file as input and feeds data t-code 'VK11' in BDC call transaction mode. It is generating the error No batch input data for screen SAPMV13A 0122. If in debug mode before the call transaction we change the value of mode to 'A' (all screens), then no error is generated and document is posted successfully. But if the mode is kept 'N', then the the error comes. Can anyone have any idea, why the result is different in mode A and N? What is the solution of this problem?