Run time error in ALV editable

Hi Gurus

I am getting a run time error when I edit a field in the ALV report and press enter. The run time error is : GETWA_NOT_ASSIGNED. It says I tried to access an unassigned field symbol. I have not used any field symbols in my field catalog or anywhere. It also says that the location of the termination was : cl_gui_alv_grid .

I have to get this report working today at anycost. Any help will be very useful