datastage buildop error - buildop throwing the error

Question

I am getting the following error message, when I am running a job in datastage. The buildop stage is throwing this error

    isUsable() is false on the accessor interfacing to field "getEditsReturn"

The filed is input field.

getEditsReturn is the only input column to buildop.

The code is

   while(!inputDone(0)){

       readRecord(0);

       input = inputData.getEditsReturn;

       fprintf(fp,"input : %s",input.c_str());

        //break the string based on delimiter and assign to output columns

       transferAndWriteRecord(0);

       }

Here input is the c++ string type(not char[]). I tried to assign the input column to char[] also. It was also not working. I have set autoread and autowrite to false. I am writing those output columns to a file using fprintf. I am getting that output correctly in the file. But the stage is failing