Import statemnt is not getting one of the field in internal table
I am running two programs YP1 AND YP2 , in yp1 I am exporting the data to yp2, in YP1 all of the field is present including wtjhr which is field of bpja stucutre, but when I import the data in yp2 , all of the is field is displaying correctly but wtjhr is showing zero ,I checked the corresponding structure bpja in which wtjhr is updated correctly, but when I imported data this value showing null value,
Here is my import/export statement in both reports
export tab4 from tab4 to database indx(st) from wa_indx id indxkey.
free memory id sy-uname.
And in Yp2
tab4 = tab4 from database ypindx(st) id indxkey
Please help me in this regard as I am new to abap I have goggled this problem but could not find any help ,
Thanks in Advance.