Open the form design and check whether the fields are there. if fields are present, check the position of the fields whether they are overlapping also check the properties whether visible is yes. If it was overlapping, give the current position i.e “LEFT” , “HEIGHT” , “TOP”, “WIDTH” …
Take a back up of that report. Duplicate that report. in Duplicated report, delet the fields which are not displaying and again add the fields which u want from the datasource…in menuitem button, change the duplicated report name… In PO form, inquiries, run the PO report and check whether the fields are displaying…