Tables

I hav added some rows in a tables n can be deleted checking the checkboxes next to each row. aafter deletion i hav changed all the objects in the undeleted rows to the same order of the names i had before deletion.Everything is working fine..but when i go for a second round of deletion ,null object error is getting displayed.But if u check the names of the objects,u can find the object vth that name in the tables..i need a function refreshment..can anyone help me in this issue